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THE 

SUBWAYS AND TUNNELS 

OF NEW YORK 
METHODS AND COSTS 



WITH AN APPENDIX ON TUNNELING MACHINERY AND 
METHODS AND TABLES OF ENGINEERING DATA 



BY 



GILBERT H. GILBERT, LUCIUS I. WIGHTMAN 

' AND 

W. L. SAUNDERS 

f 



FIRST EDITION 
FIRST THOUSAND 



NEW YORK 

JOHN WILEY & SONS 

London: CHAPMAN & HALL, Limited 

1912 






Copyright, 1912, 

BY 

GILBERT H. GILBERT, LUCIUS I. WIGHTMAN 

AND 

' W. L. SAUNDERS 



,u 







THE SCIENTIFIC PRESS 

ROBERT DRUMMOND AND COMPANY 

BROOKLYN, N. Y. 



4 tjr-o * 

£CLA312565 



TRIBUTE 



No record of tunneling under the rivers surrounding New 
York is complete without a tribute of admiration and respect 
to the genius and ability shown by the men who were the 
architects and builders. It has for a long time been an easy 
matter to tunnel through rock. The power drill simply added 
to the efficiency of rock tunneling and in doing this it was made 
possible to build great tunnels for railways, aqueducts, etc., 
within a reasonable time and at reasonable expense. 

To build and maintain tunnels through silt or other alluvial 
material, especially tunnels of large diameter, was a problem 
which had not been solved by engineers as late as 1874. At 
that time Mr. Delos E. Haskin came to New York from San 
Francisco, where he had made a fortune, every dollar of which 
he lost in an effort to prove the practicability of tunneling under 
the Hudson River and through the silt by means of compressed 
air. Though Haskin did not live to enjoy the fruits of his work, 
he proved the practicability of his scheme in a general way and 
to him belongs the credit as the genius who pushed the idea to the 
front. 

Next came Mr. Charles M. Jacobs, who combined the genius 
and enthusiasm of Haskin with the ability of the engineer. Mr. 
Jacobs built the first tunnel under the rivers about New York, 
namely, the East River Gas Tunnel from New York to Brooklyn. 
After this he took up with enthusiasm the completion of the old 
Haskin tunnels, maintaining with earnest zeal the practicability 
of the scheme, modified on lines of his own experience, until 
he succeeded in completing these and the Pennsylvania tunnels, 
which are described in this volume. In the darkest days of 



vi TRIBUTE 

tunneling under these rivers Mr. Jacobs never lost courage. 
When the work began he was on the job at all times, and his 
genius and engineering capacity are shown throughout this 
great work. He has now returned to his home in England, 
and well does he deserve the reputation and wealth which he 
has achieved. 

Mr. William G. McAdoo, with great foresight and ability, 
planned and executed that gateway to New York, through 
tunnels under the Hudson, which is called the McAdoo System. 
Of these three men Haskin was the enthusiast, Jacobs the engi- 
neer and McAdoo the business man. 

W. L. Saunders. 



PREFACE 



The system of subways and tunnels in and about New York 
City is the result of traffic conditions which are entirely without 
parallel in any other city of the world. The island of Man- 
hattan, comprising the Borou h of Manhattan of the City of 
New York, is a little less than twelve miles in length and, at 
the widest point, a trifle over two miles in width; yet it is the 
business center of a population aggregating probably close to 
six millions. The census of 1910 credits New York City with a 
population of something over four millions. But when to this 
figure are added the inhabitants of the adjacent cities in New 
Jersey, New York and Connecticut which are within commuting 
distance, six millions is probably a fair estimate of the popula- 
tion, the business pivot of which is found in the island of Man- 
hattan. The actual business center for this vast number may 
be further restricted to a section south of 426. Street, the upper 
part of the island being principally residential in character. 

A consideration of these figures will reveal the magnitude 
and complexity of the traffic problem in New York City. 
The East River intervenes between Manhattan and the 
Boroughs of Brooklyn and Queens, and the suburban towns 
of Long Island New York Bay separates the Borough of 
Richmond (Staten Island). The Hudson River divides the 
industrial and suburban territories of New Jersey from New 
York. On the north, the Harlem River divides the Borough 
of the Bronx, and the towns of New York State and Connecticut, 
from their business center. 

Every business day in the year a vast tide of humanity 
converges on the business center of New York City. Through- 

vii 



viil PREFACE 

out the business day a large percentage of these business men 
and women, and shoppers, must be furnished quick and safe 
transportation within the limits of the island. Every evening 
this tide diverges to its homes. This morning and evening 
migration must all be accomplished within the space of an hour 
or so. The magnitude of the transportation problem here 
presented has called for the greatest engineering genius and 
almost unlimited capital; and its solution — by no means com- 
plete as yet — finds its beginning in the transit system of which 
the New York subway, and the North and East River tunnels 
with their connections, are a part. 

The ferry systems from New Jersey, Long Island and Staten 
Island have reached the limit of their capacity. The East 
River bridges furnish relief to the situation, but are by no means 
sufficient. The elevated and surface car systems of New York 
and Brooklyn have been extended to their practical limit. 
With surface, above-surface, and over- water means of transit 
incapable of further expansion, the only alternative was to make 
use of the subterranean and subaqueous territory underlying 
and adjacent to the greater city. The subways, and sub- 
aqueous and land tunnels, in and about New York City may be 
considered as simply a beginning of a vast system of sub -surface 
transportation which must develop with the growth of population. 

The present Interboro Rapid Transit Subway consists of a 
trunk line starting in Brooklyn, passing under the East River, 
entering Manhattan at the Battery, and following the back- 
bone of the island to its northern extremity, with a branch to 
the Bronx passing under the Harlem River. 

The Pennsylvania Railroad and Long Island Railroad sys- 
tem comprises a series of surface, subaqueous and subterranean 
lines starting at Harrison, N. J., crossing the meadows on the 
surface, penetrating Bergen Hill by tunnel, plunging beneath 
the Hudson, or North River, through two subaqueous tunnels, 
traversing Manhattan through the crosstown tunnels, passing 
beneath the East River through four subaqueous tunnels, and 
emerging on the surface at Long Island City. This system 
may be said to properly include the great Pennsylvania Passen- 



PREFACE 



IX 



ger Terminal in New York City, with its sub-surface yards. 
Its object is not only to give quick access to the heart of Man- 
hattan for the commuting service of Long Island and portions 
of New Jersey, but to provide also a city terminal for the Penn- 
sylvania through traffic from the West. 

The so-called McAdoo System is for suburban service 
entirely. It includes: A sub-surface belt line, or tunnel, along 
the Jersey shore connecting three railroad terminals; four 
subaqueous tunnels under the Hudson; and a line of subway 
from the terminus of two of its Hudson River tunnels northward 
under Manhattan Island. 

Under the East River are the Belmont tunnels, completed 
but not yet in operation, from Long Island to Manhattan. 
They will, probably, later be made a part of the great traffic 
arteries of New York. 

The tunnel and subway system serving the population 
centering in New York thus includes: One complete subway 
system connecting three boroughs; eight subaqueous tunnels 
under the East River; six subaqueous tunnels under the Hud- 
son River to the mainland; two subaqueous tunnels under the 
Harlem River to the Bronx; the belt-line tunnels and the 
New York subway of the McAdoo System; and the Bergen 
Hill and crosstown tunnels of the Pennsylvania Railroad. 

In the aggregate these enterprises probably involve as much 
capital as the building of the Panama Canal — and possibly 
even more. They have encountered at every stage obstacles 
stupendous in magnitude and difficulty, and calling for engineer- 
ing methods beyond all precedent. They represent engineering 
and contract achievement of such vast importance that they 
mark a new era in construction work. 

The authors here acknowledge their indebtedness to the 
many engineers and contractors whose records and papers have 
furnished so much of the information in these pages. Individual 
credit has been given in many places throughout the book. 
But in many cases the authority is not stated, simply because 
the data given is a compilation from a number of sources. 
Acknowledgment is also made to the Ingersoll-Rand Company 



x PREFACE 

and to the Cameron Steam Pump Works for photographs and 
tables of engineering information; to the American Society of 
Civil Engineers for the use of many valuable plates and illus- 
trations; and to Compressed Air Magazine, from which several 
important papers, with their illustrations, have been taken. 

The Authors. 



CONTENTS 



PAGE 

Tribute v 



Preface 



vii 



CHAPTER I 
Topography, Geological Formation and Historical Data i 

CHAPTER II 
The Original Hudson Tunnel 7 

CHAPTER III 
The East River Gas Tunnel 10 

CHAPTER IV 

Manhattan-Bronx Division of the New York Subway 16 

CHAPTER V 

The Brooklyn-Manhattan Division of the New York Subway. . 27 

CHAPTER VI 

Compressed Air in the Subway Construction; Costs of Exca- 
vation in the New York Subway 32 

CHAPTER VII 

The Pennsylvania Railroad Developments in and near New 

York City 37 

xi 



xii CONTENTS 

CHAPTER VIII 

PAGE 

Bergen Hill Tunnels of the Pennsylvania Railroad 46 

CHAPTER IX 

North River Tunnels of the Pennsylvania Railroad 57 

CHAPTER X 

North River Tunnels of the Pennsylvania Railroad — {Continued) 68 

CHAPTER XI 
North River Tunnels of the Pennsylvania Railroad — {Continued) 77 

CHAPTER XII 

Excavation for the Terminal Station of the Pennsylvania 
Railroad 91 

CHAPTER XIII 
Cross-town Tunnels of the Pennsylvania Railroad 104 

CHAPTER XIV 
The East River Tunnels of the Pennsylvania Railroad in 

CHAPTER XV 
The East River Tunnels of the Pennsylvania Railroad — {Cont.). 123 

CHAPTER XVI 
The East River Tunnels of the Pennsylvania Railroad — {Cont.). 133 

CHAPTER XVII 
The East River Tunnels of the Pennsylvania Railroad — {Cont.). 143 

CHAPTER XVIII 

The Belmont Tunnels . 148 



CONTENTS xiii 

CHAPTER XIX 

PAGE 

The Hudson-Manhattan Tunnels 145 

CHAPTER XX 
The Hudson-Manhattan Tunnels — {Continued) 150 

CHAPTER XXI 

The Hudson Terminal Station of the Hudson-Manhattan 
Tunnels 158 



APPENDICES 

APPENDIX A 

Air Compressors in the New York Tunnel Work 185 

APPENDIX B 
The Compressed Air Plenum 205 

APPENDIX C 
The Use of Compressed Air in Tunneling 210 

APPENDIX D 
Special Types of Air Compressors 217 

APPENDIX E 
Straight Line and Duplex Compound Air Compressors 226 

APPENDIX F 

Compound Air Compression; Altitude Compression; Air Cylin- 
der Lubrication 237 



xiv CONTENTS 

APPENDIX G 

PAGE 

Some Air-lift Data ..„. 251 

APPENDIX H 
Compressed Air Locomotives 256 

APPENDIX I 
Rock Drills; Hammer Drills 262 

APPENDIX J 

Tunnel Carriage for Drilling; Electric-Air Drill. 281 

APPENDIX K 
Rock-Drill Bits; Drill Sharpening 295 

APPENDIX L 

Explosives; Dampness and Dynamite; Blasting Gelatine; 
Cost of Blasting in Open Cuts 307 

APPENDIX M 
Pumps for Sinking and Tunneling; Sinking Caissons 319 

APPENDIX N 
Engineering Data . . 34c 



SUBWAYS AND TUNNELS OF NEW YORK 



CHAPTER I 
TOPOGRAPHY, GEOLOGICAL FORMATION AND HISTORICAL DATA 

The island of Manhattan is a rocky ridge lying north and 
south and having an area of approximately 14,000 acres or 22 
square miles. It is in the upper end of New York Bay, between 
the Hudson River on the west and the East River on the east, 
with the Harlem River and Spuyten Duyvil Creek, small con- 
necting tideways, separating it from the mainland on the north 
and northeast. 

Manhattan Island, as well as the adjacent country to the 
north and east, is principally a formation of rock composed 
chiefly of gneiss and mica schist, with heavy seams of coarse- 
grained dolomitic marble and thinner layers of serpentine run- 
ning through it. These rocks are supposed to be Lower Silurian 
in character. Rocks of the Lower Silurian era are mainly 
sandstone, shales, conglomerates and limestones; but Pro- 
fessor Newberry holds that they have so great a similarity to 
some portions of the Laurentian Range in Canada, that it is 
difficult to evade the conviction that they are of the same period. 

The deep troughs, through which the Hudson and East 
Rivers find their way through New York harbor to the ocean, 
are supposed by the same authority to have been excavated 
during the late Tertiary period when Manhattan Island and 
the other islands in New York Bay stood much higher than they 
do now, when Long Island did not exist, and when a great sand 
plain extended beyond the Jersey coast some eighty miles 
seaward. 



SUBWAYS AND TUNNELS OF NEW YORK 




SECTION L M 
about 175th St. 




SECTION I K 
about 110th St. 




SECTION G H 
about 95th St. 





SECTION A B 
about Park Place 



SECTION C D 
about 10th St 

City Hall ' . „ , „ . 

Sand-Made Ground 
Clay-River Mud 
Sand 
Clay 
Sand 
Clay 
Sand 

Gravel 125 ft. down 
Gneiss 



Y////A 



Cross-sections of Manhattan Island, 
showing Geological Formations. 



For half its length north- 
ward from its lower point, 
Manhattan Island slopes on 
either side from a central 
ridge. On the upper half of 
the island the ground rises 
precipitously from the Hud- 
son River in a narrow line of 
hill which on the eastern side 
sinks rapidly to a plain known 
as the Harlem Flats, border- 
ing on the Harlem and East 
Rivers. The surface through- 
out the island is rocky, with 
the exception of this plain. 

The district beyond the 
Harlem River, as far north as 
Yonkers, is traversed by lines 
of rocky hills trending north 
and south. Some idea of the 
varied outline which was once 
characteristic of the whole 
island can be gathered from 
the present surface formation 
of Central Park. The bed of 
the Hudson River is a deposit 
resulting from the washing 
away of the rocks of the upper 
river in the form of silt, shale, 
sandstone or other sedimen- 
tary or metamorphic rock, 
and a trap rock of the Pali- 
sades formation. 

Note. From Dana's Geology; 
Newberry's Geological History of New 
York Island; Edwin L. Godkin, En- 
cyclopedia Britannica; Report of the 
Chamber of Commerce of the State of 
New York, 1905. 



TOPOGRAPHY, GEOLOGICAL FORMATION, ETC. 



Underbliff 



Weeha 



Jersey 




Long Island City 



Williamsburg 



Hoboten 



Navy Yard 



Approximate Line of The Tunnel— 

Geological Map of Manhattan Island, with Route of the Original Rapid 

Transit Subway. 



4 SUBWAYS AND TUNNELS OF NEW YORK 

From the first settlement of Manhattan Island by the Dutch, 
two or three years after Hudson's visit in 1609, until 1700, the 
population had become about 21,700 In 1800 this had grown 
to 60,500; in 1820 to 124,000. From that time the population 
has increased until it has successively covered the district south 
of Wall Street, south of Canal Street, south of 23d Street, south 
of 42d Street, south of the Harlem River; and it now extends 
north of the Harlem along the Hudson River well toward Yon- 
kers, and on the east toward Long Island Sound. 

The population of the municipality is, as already stated, 
approximately four millions. 

The first settlement was at the extreme southern end of the 
island The commerce of that day was gathered at this point, 
and this section remains to-day the great center of finance, 
trade and commerce. The metropolitan center, including the 
nearby cities of New Jersey, New York and Connecticut, 
embraces a total population of probably six millions and is, 
with the exception of London, the largest center of population 
in the world. The growth from south to north, covering an 
extent of more than ten miles, has been restricted on the eastern 
and western sides by the East and Hudson Rivers. The con- 
ditions of growth and population have demanded rapid and 
certain means of travel between the different sections and the 
general center. 

At the beginning of the last century small stages met all 
transit requirements. With the advent of steam ferries, about 
1820, transportation across the rivers was facilitated. In 1850 
stage and omnibus lines served the population and were a little 
later superseded by tram cars. 

Rapid transit in a sense somewhat approaching the present 
understanding of the term was introduced in 1875, when trains 
were brought into the Grand Central Station at 42d Street 
over a four-track system. A short section of elevated railroad 
had been erected in Greenwich Street in 1870. Ten years later 
elevated railway structures had been completed to the Harlem 
River. The opening of the Brooklyn Bridge in 1883, and the 
further extension of the system of elevated roads, brought the 



TOPOGRAPHY, GEOLOGICAL FORMATION, ETC. 5 

outlying districts within reasonable traveling time of New York 
City. In 1884 the cable system of propelling street cars was 
introduced, to be later displaced by electric railway systems. 

From 1868 to 1900 many projects and schemes were put 
forth to improve transit facilities Among the first was the 
Beach Pneumatic, incorporated in 1868, and known as the 
Broadway Underground Railway. It was the only one upon 
which constructive work was actually done. The charter of 
this company provided that, to demonstrate the practicability 
of its plans " to transmit letters, packages and merchandise, 
etc., it must first lay down and construct one line of said 
pneumatic tubes, etc." A full-sized section of the tunnel was 
built on the lines adopted and is to-day in good condition. 
In 1873 this company's charter was amended to permit it to 
construct, maintain and operate an underground railway for 
the transportation of passengers and property. It was pro- 
posed to operate the tunnel by means of compressed air, a car 
circular in cross-section being used, approximately fitting the 
interior of the tube. It was pointed out that by this means 
the obnoxious gases from the combustion of coal in locomo- 
tives would be done away with. 

Work was begun on the tunnel at the corner of Broadway 
and Warren Street, and a section was built under Broadway 
to the southern side of Murray Street. The straight portions 
of the tunnel were lined with brick to a diameter of eight feet 
in the clear; the curved portions were of cast iron. The 
tunnel was built by means of a shield, which was forced forward 
two feet at a time by hydraulic jacks. 

Early in 1870 the tunnel was open for inspection. A car 
was run from one end to the other with the object of demon- 
strating the safety and practicability of the plan. The work 
done failed of successful issue. Engineers were divided in 
opinion as to the possibility of building an underground tunnel 
under narrow streets in front of such massive structures as 
the Astor House. Owing to this difference of opinion on the 
part of the experts financial support could not be obtained 
and the project was dropped. 



6 SUBWAYS AND TUNNELS OF NEW YORK 

In 187 1 the Gilbert Elevated Railroad was chartered for 
the purpose of constructing a pneumatic tube railway. It was 
proposed to erect a pneumatic tube, supported from arches 
above the street. It was claimed that the road would be 
noiseless and the train out of sight. This plan was found 
impracticable and too expensive, and it was decided to build 
the tube without a top, and to operate a steam road in the 
trough thus formed. Finally the trough also was abandoned 
and the plan resolved itself into a simple elevated railroad, 
the outgrowth of which are the present elevated railway systems 
of the city. 



CHAPTER II 

THE ORIGINAL HUDSON TUNNEL 

In 187 i D. C. Haskins conceived the idea of building a 
tunnel under the Hudson River. In making a trip from the 
Pacific Coast via Omaha he had been struck with the system 
of building piers for a railway bridge over the Missouri River. 
This system was the forming of caissons made up of a number 
of iron rings bolted together and constituting a cylinder which 
could be lengthened by the addition of rings as the caisson 
descended. Air locks and compressed air were used, the material 
within the caisson being excavated by hand till a bed rock 
foundation was reached. 

From a study of this work Mr. Haskins conceived the idea 
that iron cylinders fitted with air locks could be placed horizon- 
tally, and tubular tunnels under the Hudson River could be 
started from the bottom of a shaft by using compressed air 
to prevent the inflow of earth and water. As the material 
was excavated in front of the tunnel the latter was to be 
advanced by the addition of rings of the diameter of the finished 
tube. Work on such a tunnel under the Hudson River to con- 
nect New Jersey and New York was commenced on the New 
Jersey side in November, 1874. The bed of the Hudson is a 
silt deposit, which when dry is an impalpable powder, but when 
saturated with water is as fluid as quicksand. When a certain 
degree of moisture is carried by this material it has a con- 
sistency approximating that of clay. This latter character- 
istic was taken advantage of by maintaining an air pressure 
in the heading equal to the hydrostatic head outside, when the 
material to be excavated formed a barrier against the entrance 
of water, thus permitting the heading to be advanced. The 
work began with sinking a shaft 38 feet in outside diameter, 



8 SUBWAYS AND TUNNELS OF NEW YOKK 

lined with 4 feet of brick work to a depth of 54 feet below 
mean high water. On opposite sides of the shaft, in the direc- 
tion of the length of the tunnel, false pieces of elliptical form, 
26 feet high and 24 feet wide, were built. These were to be 
removed to permit the passage of the tunnel. An air lock, 
6 feet in diameter by 15 feet long, was attached to the shaft 
cylinder above the false piece on the east side. A temporary 
working entrance to the tunnel was formed of eleven rings, 
each 2 feet wide, but of different diameters. The tops of these 
rings were in the same horizontal line, forming a cone-shaped 
chamber with steps of 18 inches leading to the air-lock. 

From the base of this cone, which was 20 feet in diameter, 
two parallel single track tunnels were started. As the largest 
ring was not large enough to take in both tunnels, a ring of a 
diameter equal to the exterior of the north tunnel was built 
and lined with 2 feet of brick work. Regular tunnel work was 
then commenced. Silt was excavated till the top center plate 
of a new ring could be placed and bolted to the one behind; 
then plates were bolted to either side of this top plate until 
the ring was completed. When four rings of plate, equal to 
10 feet of section, had been placed, and the heading cleared out, 
the masonry was laid. The plates were of quarter-inch iron, 
2\ feet in width by 3^ feet in length, flanged on all four sides 
with angle iron. The tunnels were 18 feet high by 16 feet wide, 
inside dimensions. 

The air pressure was kept about equal to the hydrostatic 
head, amounting to 18 pounds at the shaft and increasing 
to 36 pounds at a distance of 1600 feet. No fixed rule could 
be given to govern the air pressure, but it was found generally 
that a little less than the hydrostatic pressure at the axis of the 
tunnel gave the best results under ordinary conditions. The 
excavated chamber was 23 feet in diameter, so that the dif- 
ference of water pressure between the top and bottom of the 
chamber was about 11 pounds per square inch. Under these 
conditions some air escaped through the roof and some water 
entered through the bottom. Excessive pressure resulted in 
an increased discharge of air through the roof, causing the 



THE OKIGINAL HUDSON TUNNEL 9 

silt to dry out and drop into the tunnel. If this mass was suf- 
ficient a blow-out and consequent flooding resulted. 

When the north tunnel had been advanced over a quarter 
of a mile the south tunnel was started, and when this had been 
carried forward some distance both tunnels were bulkheaded; 
and work on the removal of the temporary entrance was 
commenced. 

A serious blowout occurred in July, 1880. The doors of 
the airlocks had become wedged by falling earth and plates, 
cutting off the escape of the men, twenty of whom were drowned. 
This accident had an unfavorable effect upon the financial 
aspect of the undertaking. 

The New York end was started by sinking a timber caisson 
48 by 29^ feet to a depth of 56 feet below high water, where it 
was fully imbedded in sand. Through the west side of this 
caisson, on the line of the tunnel, an opening was cut and roof 
plates of the tunnel put in and braced. Plates were added 
till a section 12 feet long had been built, when an iron bulk- 
head was constructed. In building additional sections the 
same system was adopted. As each section of the iron tube 
was completed it was cleaned out and the brick lining laid. 
This was the first and only instance of building a subaqueous 
tunnel in sand without the aid of a shield. 

S. Pearson & Son of England assumed the contract in 1888, 
Sir John Fowler and Sir Benjamin Baker acting as consulting 
engineers. The shield method of driving was adopted and 
heavy iron plates were substituted for masonry. The light 
boiler plate lining was no longer required. The work was 
stopped through lack of capital and unsuccessful attempts 
were made at various times to resume the operations until 
the early part of 1902. In that year the franchise and property 
of the tunnel company were acquired by the New York and New 
Jersey Railroad Company, and operations were again started. In 
1905 the New York and New Jersey Railroad Company disposed 
of their interests to the Hudson Company, who have since com- 
pleted the tunnels. The completion of this work, which is now 
known as the McAdoo System, is described in another chapter. 



CHAPTER III 

THE EAST RIVER GAS TUNNEL 

The first completed tunnel under the East River, that of 
the East River Gas Company, for the transmission of illuminat- 
ing gas from the gas works on Long Island for distribution 
throughout Manhattan, was of unusual interest and importance 
in that its successful completion demonstrated the entire pos- 
sibility of constructing similar tunnels under the same water- 
way wherever they may be required; and also in that the prog- 
ress of the work revealed the peculiar conditions and the special 
difficulties which might be expected to be encountered in similar 
undertakings in the same neighborhood. 

This tunnel was not as large in section as would be required 
for a standard railroad, or even for trolley cars and general 
traffic, but it was still large enough to reveal all the difficulties 
which a larger construction would have involved. The rock 
section was required to be Sh feet high and 10 feet wide, and 
the heading was driven the full width. The location of the 
tunnel is from Webster Avenue, Ravenswood, Long Island, 
under both channels of the East River, with Blackwell's Island 
between them, to Seventy-second Street, Manhattan. The roof 
grade of the tunnel was 40 feet below the lowest point in the bed 
of the river, which was in the west channel and in feet below 
mean high water mark. The water in the east channel was 
not more than half as deep as that in the west channel so that 
the depth of ground over the tunnel was there much greater. 

Preliminary investigation revealed bed rock on both sides 
of the river only a few feet below the surface and also on the 
island; and drill soundings made with difficulty in both channels 

10 



THE EAST RIVER GAS TUNNEL 11 

seemed to show from two to five feet of sand and gravel at the 
bottom and then solid rock, so that the driving of the tunnel 
was expected to be a clean and uninterrupted job straight 
through and the contract for the job was placed on that 
basis. 

Work was begun by the contractors, McLaughlin, Reilly 
& Co., at the Long Island end June 28, 1892. Bed rock was 
found 9^ feet below the surface, being a compact gneiss almost 
approaching granite. Work commenced on the New York 
end July 10. The rock here was the regular micaceous gneiss 
known as " New York rock." The rock in the New York shaft 
was straight grained with a dip of about 10 degrees from the 
vertical, striking nearly north and south and becoming harder 
as the depth increased. No water or any abnormal difficulties 
were encountered and the bottom of the shaft was reached at 
the end of October, 139J feet below the surface. At the Long 
Island shaft the progress was not so rapid. The rock was seamy 
and much water was encountered. There was no reliable water 
supply for the boilers and the water obtainable, although not 
salt, was entirely unfit for use and there were numerous stoppages 
during the entire continuance of the work on account of the 
water supply. 

The care and precision with which the line was laid are 
indicated by the fact that when the headings met, 1678 feet 
from the New York shore, the lines were within \ inch of each 
other laterally and i\ vertically. 

Two Ingersoll-Sergeant compressors were installed at each 
end of the tunnel, and drills of the same company were em- 
ployed throughout the work. On the New York end the 
driving of the heading proceeded to a distance of 348 feet, when 
a seam of decomposed rock was struck, a straight face across 
the heading. After advancing into this 9 feet it was found 
unsafe to proceed, the ground finally having reached " about 
the consistency of soup." A steel air lock 6 feet in diameter and 
10 feet long, was made and fastened solidly in the rock. Work- 
ing under air pressure was commenced, the initial pressure 
being 35 pounds; electric lighting was installed. 



12 SUBWAYS AND TUNNELS OF NEW YORK 

The heading was enlarged and changed to a circle 12 feet 
in diameter. The tunnel in this part was lined as it advanced 
with light plates of wrought iron connected with angle irons, 
and 12 inches of brick work was laid inside the plates. One- 
half of the thickness of the brick was subsequently removed 
and a lining consisting of cast iron segments bolted together 
finished the job. 

The working air pressure was ultimately raised to 48 pounds, 
which was higher than men had ever worked in before, and they 
began to experience serious difficulty in continuing the work. 
Four deaths in all resulted from the air pressure, and there 
were no other deaths or accidents in the entire progress of the 
work. The first man to die was a foreman. The second man 
had been long out of employment and was in very low condi- 
tion. He died in the air lock after his first shift of two hours. 
The third man became paralyzed from his shoulders down and 
died soon after. The fourth man died nearly a year after the 
others. 

In connection with this feature of the work the following 
rules for men working in compressed air were formulated by 
Dr. Andrew H. Smith of the Presbyterian Hospital: 

1. Never enter the airlock with an empty stomach. 

2. Use as far as possible a meat diet, and take warm coffee 
freely. 

3. Always put on extra clothing when coming out, and 
avoid exposure to cold. 

4. Exercise as little as possible during the first hour after 
coming out, and lie down if possible. 

5. Use intoxicating liquors sparingly. Better not at alL 

6. Take at least eight hours sleep every night. 

7. See that the bowels are evacuated every day. 

8. Never enter the lock if at all sick. 

9. In exit from the air lock, the time occupied should be 
five minutes for each atmosphere above the normal. 

The earliest injurious effect experienced is an itching caused 
by air globules in the capillaries, which may be quickly cured 
by inducing profuse perspiration. 



THE EAST RIVER GAS TUNNEL 13 

The " bends," a more serious trouble, is an intense rheumatic 
pain in the joints caused by air globules in the sockets. 

Paralysis leaves lasting injury and is usually the cause of 
death when it occurs. 

A highly steam heated dressing room was found beneficial, 
with copious supplies of hot, strong coffee. 

For pressures up to 30 pounds the men worked two shifts 
of four hours each, with one hour of rest between. For the 
highest pressure the men worked only 1^ hours at a time, and 
4! hours for the entire day. 

The information herein contained is mostly abstracted from 
the report of the chief engineer, Mr. Charles M. Jacobs, Mem. 
Inst. C.E., Mem. Inst. M.E. The following narration of a 
bit of experience of Sunday, March 26, 1893, is quoted from the 
report. 

" In order to keep an exact record of the air pressure I had 
fitted up an Edison automatic recording pressure gage with 
high and low pressure alarm bells attached. The foreman of 
the contractors with the engineer had broken the lock and 
removed the pencil. The fires were nearly out and the com- 
pressors were stopping, the pressure having fallen 11 pounds. 
A large quantity of soft ground had worked into the heading, 
entailing more exercise of ingenuity and determination to get 
things going right again. A great cavity had washed in and 
the water was bringing it down continuously." 

In the progress of the work serious troubles occurred with 
the contractors, who finally abandoned the entire contract. 
At one point they had to be restrained by injunction from 
removing their compressors at a critical time. The air pres- 
sure would not have been maintained and a general collapse 
might have resulted. The matter became a subject of litigation. 

At the Long Island end of the work the troubles had their 
own individuality. Bad and insufficient water for the boilers 
caused frequent stoppages, while it was essential to keep the 
pumps active to prevent drowning out. The first soft ground 
was met 253 feet from the shaft, and at 285 feet a green, slimy, 
and almost liquid material began oozing out, which so embar- 



14 SUBWAYS AND TUNNELS OF NEW YORK 

rassed the contractors that they then abandoned the work, 
allowing the heading to fill with water. 

The stringency of the money market in 1893 was another 
incident which caused a cessation of all operations for a couple 
of months. 

A neighboring picnic place, " Jones's Woods," took fire 
and with it was destroyed the entire plant at the New York 
end, and before pumps and compressors could be installed the 
heading was drowned out again. 

The time of greatest anxiety, difficulty and risk was when, 
in advancing the shield at the New York end, a shelving bank 
of rock was found in front of the bottom of the shield, while 
at the top was the softest black mud. It was necessary to 
blast out this rock in the floor in advance of the shield and to 
get through the bulkhead which had been put in when the 
work had been abandoned. Direct communication was opened 
with the river, so that refuse and even live crabs came into 
the tunnels. The leakage of air was so great that both com- 
pressors at the limit of their speed had difficulty in maintaining 
the pressure of 48 pounds. The difficulties continued until 
the shield was entirely entered into the black mud, when the 
pressure was reduced and the shield was advanced at the rate 
of 6 feet per day. The shield was pushed forward by twelve 
hydraulic jacks with a combined thrust of 600 tons. The 
second soft place extended 98 feet. The rock ahead was badly 
seamed, but finally became solid again and then in two weeks 
101 feet and 94.6 feet advance respectively was made, which 
rate had never been surpassed in that class of rock. 

The headings met July 11, 1894, 1676 feet from the New 
York shaft. The total distance from shaft to shaft was 2550 
feet, so that two-thirds of the length was driven from the New 
York end. When working in solid rock the average progress 
was 69 feet per week. Bonuses were given to foremen and to 
some of the gang leaders. 

Considering the unexpected difficulties encountered and the 
delays from so many different causes, the total time from the 
beginning to the completion of the tunnel, a few days over two 



THE EAST RIVER GAS TUNNEL 15 

years, must be considered remarkable, and could only have 
been possible with constant resourcefulness and untiring push. 
After the ends met there was little more to be done and in a 
very short time a 36-inch gas main was laid with an uninterrupted 
motor car track at the side of it. — From Compressed Air 
Magazine. 



CHAPTER IV 

MANHATTAN-BRONX DIVISION OF THE NEW YORK SUBWAY 

In January, 1890, the contract for the Manhattan-Bronx 
division of the New York subway was awarded and the work 
of construction was undertaken by the Rapid Transit Subway 
Construction Company. The work was to be done in four 
sections, as follows: 

Section 1 extended from the southern terminus at City 
Hall to and including the station at 59th Street and Broad- 
way; it comprised five miles of four- track subway. 

Section 2 included all railroad from the north end of the 
59th Street station to and including the station at 137th Street 
and Broadway; and on the east side from the junction of 
103d Street and Broadway to and including the station at 
135th Street and Lenox Avenue. This section comprised 3.43 
miles of two-track subway and 0.51 mile of three-track viaduct. 

Section 3 included all railroad on the west side, northward 
from the station at 137th Street and Broadway, to and includ- 
ing the station at Fort George; and on the east side from the 
station at 135th Street and Lenox Avenue, to and including the 
station at Melrose Avenue. This comprised 4.32 miles of two- 
track subway. 

Section 4 comprised the remainder of the road, from Fort 
George to Kingsbridge on the west side and from Melrose 
Avenue on the east side, including 5.29 miles of two-track 
viaduct. 

The prices to be paid were as follows: 

Section 1 $15,000,000 

Sections 1 and 2 26,000,000 

Sections 1, 2 and 3 32,000,000 

Sections 1, 2, 3 and 4 35,000,000 

The cost of equipment was estimated at $6,000,000. 

Note. From Report of the Chamber of Commerce of New York State, 1905; 
The New York Subway, issued by the Interborough Rapid Transit Company. 

16 



SUBWAYS AND TUNNELS OF NEW YORK 



17 




Feet^ 



Central Park West 




119th St.- 3rd Ave. 

rose Ave.) 

Jackson Ave. 

Prospect Ave. 
Intervale Ave. 
Simpson St. 

Freeman St. 



Bcekman St. 

N. Y. A Brooklyn Bridge 



4^ Battery Park 
^Bowling Green 
jl Wall St. 
| Fulton St. 
City Hall Loop 3t». 
Chambers St. 
Worth St. 

Canal St. 
Spring St. 
Bleeker St. 



w Times Square 
1 (42udSt.) 
'1 50th St. 

Columbus Circle 
(59th St.) 

IfMGth St. 

0B|fc72ndSt. 

79th St. 

^ffNethSt. 
*■ || =9Ist St. 

^-iMeth st. 




^ Cathedral Parkway 
1% (110th St.) 

^Columbia University 
(116th St.) 



Manhattan St. 



Ship Canal 
Kingsbridge 
(225th St. 1 ) 
N.Y-C. & H.R. R.R. 



Feet 



Map of the New York Rapid Transit Subway in Manhattan and The Bronx, 
with Contour of the Lenox Avenue Branch. 



18 MANHATTAN-BRONX DIVISION 

Five designs were adopted in the construction of the Man- 
hattan-Bronx Division of the subway, as follows: 

For a length of 10.6 miles or 52.2 per cent of the total length 
of the road, the typical section has a flat roof near the surface 
with I-beams connected by concrete arches forming the roof 
and sides, supported by bulb angle columns between the tracks. 

In the Battery Park loop, for a short distance on Lenox 
Avenue and in the Brooklyn portion of the Brooklyn extension 
(later discussed), a flat roof of reinforced concrete is supported 
by bulb angle columns between the tracks. 

For a distance of 4.6 miles or 23 per cent of the total length, 
concrete-lined tunnel was used, of which 4.2 per cent was con- 
crete-lined open cut work and the remainder rock tunnel. 

An elevated road on a steel viaduct was used for about 
five miles or 24.6 per cent of the total length. 

Under the Harlem River, and under the East River for the 
Brooklyn extension, cast iron tubes were used. The construc- 
tion of the typical subway has been carried out by a variety 
of methods adapted to the different situations in accordance 
with the views of the sub-contractors doing the work. The 
work was done in open excavation by the " cut and cover ' : 
system. The distance from the street level to the rock surface 
below determined the manner of excavating trenches. In some 
places the rock came to the surface; in other places the 
subway was entirely in water-bearing loam or sand. The 
natural difficulties of construction were increased by the net- 
work of sewers, water and gas mains, steam pipes, pneumatic 
tubes, electric conduits, etc., which filled the streets. The 
surface roads and their conduits still further complicated the 
problem. 

In some places the columns of the elevated roads had to be 
shored temporarily. Where the subway passed close to the 
foundations of high buildings the shoring and other precau- 
tionary measures to insure safety were both intricate and costly; 
and a large proportion of the route was close to the surface, 
which entailed the removal and reconstruction in many places 
of the underground mains and ducts and of the projecting 



MANHATTAN-BRONX DIVISION 



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20 



SUBWAYS AND TUNNELS OF NEW YORK 



vaults and buildings, and required the underpinning of walls. 
Provision also had to be made for the maintenance of traffic 
upon the streets under which the subway was being built. 
Small sections or areas of these streets were floored or bridged 
to form a roadway for traffic while excavation was going on 
beneath. Where the rock came to the surface it was necessary 
to divert the electric surface roads to the side of the street; 
for attempts, to remove the rock from beneath the tracks 




Subway Construction at Union Square and Fourth Avenue. 

destroyed the yokes of the surface road. Open trench work 
was adopted where the roadway was sufficiently wide to per- 
mit traffic at the sides. In the case of surface tracks overlying 
the area to be excavated the tracks were hung from the lower 
chords of trusses supported at their ends on crib work. 

Between 33d and 426. Streets under Park Avenue, between 
1 1 6th and 120th Streets under Broadway, between 157th 
Street and Fort George under Broadway and Eleventh Ave- 
nue, and between 104th Street and Broadway under Central 



MANHATTAN-BRONX DIVISION 



21 



Park and Lenox Avenue, the road is in a rock tunnel lined with 
concrete. The section on the west side between 157th Street 
and Fort George constitutes the second longest double-track 
rock tunnel in the United States, the Hoosac Tunnel only 
exceeding it in length. 

From 1 1 6th Street to 120th Street on Broadway the tunnel 
is 37§ feet in wid th— one of the widest concrete arches in the 
world. On the Lenox Avenue section from Broadway and 103d 




Subway Tunnel Heading at 116th Street and Broadway: Timbering in Soft, 

Ground Over Rock. 

Street to Lenox Avenue and 110th Street under Central Park,, 
a two-track tunnel was driven through micaceous rock by 
taking out top headings and two full-width benches, the work 
being done from two shafts and one portal. All drilling for 
the headings was done by an eight-hour night shift, using per- 
cussion drills. The blasting was done early in the morning and 
the day gang removed the spoil, which was hauled to the shafts 
and the portal in cars drawn by mules. A large part of this 



22 



SUBWAYS AND TUNNELS OF NEW YORK 



rock was crushed for concrete. The concrete floor was the 
first part of the lining to be put in place. Rails were laid on 
it for a traveler having molds attached to its sides, against which 
the walls were built. A similar traveler followed with the cen- 
tering for the arch roof, a length of about fifty feet being com- 
pleted at each operation. 

On the Park Avenue section from 34th Street to 41st 
Street two separate double-track tunnels were driven below, 
and one on either side of, a double- track electric railway tunnel. 




Open Cut Subway Construction in Central Park, Lenox Avenue Branch. 

This work was done from four shafts, one at each end of each 
tunnel. At first top headings were driven at the north end of 
both tunnels and at the south end of the west tunnel; at the 
south end of the east tunnel a bottom heading was driven. The 
system of driving at the south end of the west tunnel was later 
changed from a top to a bottom heading. The rock in this 
section was irregular and the inclination of the strata gave 
rise to serious danger from slips. 



MANHATTAN-BRONX DIVISION 23 

The headings of the west tunnel met in February and those of 
the east tunnel in March, 1902. The enlargement of the tunnels 
to the full section was then commenced. A disturbance above 
the surface of the east tunnel resulted in damage to several 
house fronts. The portion of tunnel affected was bulkheaded 
at each end, packed with rubble and grouted with Portland 
cement mortar injected under pressure through pipes sunk from 
the street surface. When the interior was firm the tunnel was 
re-driven, using much the same methods employed in earth tun- 
nels where the arch lining is built before the central cone has been 
removed. To avoid further settlement of the earth the work was 
done slowly. When the lining had been completed Portland 
cement grout was again injected under pressure through holes left 
in the roof until further movement of the fill above was prevented. 

The tunnel between 157th Street and Fort George, already 
referred to as the second longest two-track tunnel in the 
United States, was put through in a short time and without 
any special difficulty. The tunnel was driven from two portals 
and two shafts, the latter at 168th and 181st Streets. The 
heading was carried north and south from each shaft. 

The Harlem River is crossed by a tunnel of twin single- 
track cast-iron cylinders 16 feet in diameter. The approaches 
on both sides are double- tracked concrete arch structures. The 
total length of the section is 1500 feet, of which 641 feet are 
of the cast-iron cylinder construction. Instead of employing 
the usual methods by the use of shields and compressed air, 
these subaqueous tunnels were formed by dredging a trench in 
the bed of the river, in which a caisson was built, within which 
the excavation was made. The bed of the Harlem River at 
this point is of mud, silt and sand, much of which was so nearly 
fluid that it was removed by a jet process. The maximum 
depth of excavation was about fifty feet. The trench was 50 
feet wide and carried to a grade of 39 feet below low water, 
this grade being about 10 feet above the subgrade of the tunnel. 
The War Department required that there be a depth of 20 feet 
over the tunnel at low water and that during construction half 
of the width of the river should be left free for navigation. 



24 



SUBWAYS AND TUNNELS OF NEW YORK 



To support a working platform three rows of piles were driven 
on each side of the trench from the west bank to the middle 
of the river, there being 38 feet in the clear between the plat- 
forms. A pile foundation was then made over the area to be 
covered by the subway. The piles were driven with 6 feet 
4 inches transversely and 8 feet longitudinally between centers. 
They were then cut off 1 1 feet above the center line of each tube 
and capped with 12-inch square timbers. A caisson in which 




Concrete Arch Subway Construction in Open Cut. 

to excavate the remaining material and place the iron and con- 
crete was formed of 12 -inch sheet piles for the sides and a heavy 
timber roof. As a guide and steadiment for the sheet piling 
which formed the sides of the caisson, a frame-work was built 
and sunk over the pile foundations. Transverse trusses were 
connected longitudinally at their outer ends by eight timbers 
12 inches square, so arranged that two timber stringers, 
separated to permit the passage of and to form a guide for the 
sheet piles, were bolted to the upper and lower chords at each 
end. The sheathing was driven to a depth of 10 to 15 feet below 



MANHATTAN-BRONX DIVISION 25 

the bottom of the finished tunnel. The roof, formed of three 
courses of 12-inch square timbers, separated by a 2-inch plank 
and thoroughly caulked, was then floated into position over 
the piles, loaded with earth and sunk. Three timber shafts, 
7X17 feet in plan, passed through this roof. Work in this 
caisson was carried on under air pressure, part of the spoil 
being blown out by water jets and the remainder removed 
through the air-locks in the shafts. When the excavation had 
been completed the piles were braced, the concrete and cast- 
iron lining put in place, and the piles cut off as the concrete 
bed was laid up to them. 

The eastern half of this tunnel was a modification of the plan 
just described. The side walls of the caisson were formed of 
sheet piling, but for a roof the permanent upper half of the 
tunnel of iron and concrete was used. The trench was dredged 
nearly to subgrade. Steel pilot piles with water jets were 
driven in advance of the wooden sheet piles. If boulders were 
encountered they were drilled and blasted. The steel piles 
were pulled by a hoisting engine and the wooden piles driven 
in their place. When the piling was finished a pontoon 35 
feet by 106 feet and 12 feet deep was built between the working 
platforms. Upon a false deck or floor the upper half of the cast- 
iron shells was assembled, their ends closed by steel diaphragms, 
and the whole covered with concrete. The pontoon was then 
submerged several feet, parted at the center and each half drawn 
endwise from beneath the floating top of the tunnel. The lat- 
ter was then loaded and carefully sunk in place, the connec- 
tion with the shore section being made by a diver and access 
through the roof being provided by a special opening. When 
in place men entered through the shore section, cut away the 
floor or wooden bottom and completed the caisson so that 
work could proceed. Three of these caissons were required 
to complete the east end of the crossing. 

The construction of the approaches to the sub-river tunnel 
was carried out between heavy sheet piling. The excavation 
was very wet and in places over 40 feet in depth. 

The following data cover the essential features involved 



26 



SUBWAYS AND TUNNELS OF NEW YORK 



in the building of the Manhattan-Bronx section of the subway, 
the approximate quantities of excavation and materials being 
from the chief engineer's report: 

The total length of this section of the subway is 109,570 feet. 

The total amount of excavation was 2,990,016 cubic yards of 
which 1,700,228 cubic yards were earth, 921,182 cubic yards were 
open cut rock work, and 368,606 cubic yards were rock tunnel. 




Cameron Pump for Drainage in Harlem River Tunnel, New York Subway. 



The cost of excavating was about one-third of the total 
amount of the contract. The time required for excavating was 
two-thirds of the time allotted for the completion of the job. 

The quantities of the principal materials used in construc- 
tion were approximately as follows: steel, 65,000 tons; cast 
iron, 8,000 tons; concrete, 489,122 cubic yards; brick, 18,519 
cubic yards; water-proofing materials, 775,795 square yards. 

The total length of track is 305,000 feet, of which 245,000 
feet are underground and 60,000 feet above ground. The 
contract time was four and one-half years. 



CHAPTER V 

BROOKLYN-MANHATTAN DIVISION OF THE NEW YORK 

SUBWAY 

In September, 1902, the contract for the Brooklyn-Manhattan 
branch of the subway was awarded to the Rapid Transit Sub- 
way Construction Company for $3,000,000. The route to be 
.followed was to be from the junction of Park Row under Broad- 
way, Bowling Green, Battery Place, State Street and Battery 
Park, with a loop under Battery Park and Whitehall Street. 
From there it was to pass under the East River to Furman Street, 
Brooklyn, and thence under Joralemon and Fulton Streets and 
Flatbush Avenue to the junction of Flatbush and Atlantic 
Avenues. The entire line is underground. At the Battery 
the Brooklyn line passes under the Manhattan line to avoid 
a grade crossing. The estimated cost of road and equipment 
was from $8,000,000 to $10,000,000. 

Three types of construction were used in the Manhattan- 
Brooklyn Division, as follows: 

Typical flat-roof steel beam subway from the Post Office 
to Bowling Green. 

Typical reinforced concrete subway in Battery Park, Man- 
hattan, and from Clinton Street to the terminus in Brooklyn. 

Two single-track cast-iron lined tubular tunnels from Battery 
Park under the East River and under Joralemon Street to Clin- 
ton Street, Brooklyn. 

Under Broadway, Manhattan, the work was through sand. 
The congested surface traffic, the net-work of sub-surface struc- 
tures, and the high buildings adjacent, made this one of the 
most difficult portions of the road to build. Because of the 
heavy surface traffic it was required that during construction 
the street should be maintained in a condition which would 

27 



28 



SUBWAYS AND TUNNELS OF NEW YORK 



not impede this traffic during the day time. This was pro- 
vided for by making openings in the sidewalks near the curb 
at two points and erecting temporary working platforms over 
the street, 16 feet from the surface. 

Excavation was done by the ordinary drift and tunnel 
method. The excavated material was hoisted from the open- 
ings to the platforms and discharged into wagons. On the street 
surface, over and in advance of the excavation, temporary plank 




Drilling and Mucking in East River Subway Tunnel. 

decks were placed and maintained during the drifting and 
tunneling operations, and after the permanent subway structure 
had been erected up to the time when the street surface was 
permanently restored. As the roof of the subway was only five 
feet from the street surface, gas and water mains and conduits 
had to be arranged for. These were carried temporarily on a 
trestle work over the sidewalks and when the subway structure 
was completed they were restored to their former position. 



THE BROOKLYN-MANHATTAN DIVISION 



29 



From Bowling Green, south along Broadway and State 
Street and in Battery Park, where the subway was in reinforced 
concrete, the " cut and cover ' : ' method was employed, the 




Driving Sheet Piling with an Ingersoll-Rand Sheet Pile Driver on Subway 

Construction in Brooklyn. 



elevated and surface railway structures being temporarily sup- 
ported by wooden and steel trusses and permanently supported 
by foundations resting on the subway roof. From Battery 



30 SUBWAYS AND TUNNELS OF NEW YORK 

Place, south along the loop, the greater portion of the excava- 
tion was below mean high-water level, and necessitated the use 
of heavy tongue-and-groove sheathing and the continuous 
operation of two centrifugal pumps to keep the work dry. 

The tubes or tunnels under the East River, including the 
approaches, were each 6544 feet in length. They were formed 
of cast-iron sections bolted together and had an inside diameter 



Ingersoll-Rand Rock Drills in Heading of One of the East River Subway 

Tunnels. 

of 15J feet. They were reinforced by grouting outside of the 
plates and lined inside with beton to the depth of the flanges. 
From the Manhattan side to the middle of the East River 
the tunnels were in rock and the ordinary rock tunnel drift 
method was employed, the work being carried on under air 
pressure. On the Brooklyn side beneath the river the formation 
was sand and silt. Four shields weighing 51 tons each were 
used and a hydraulic pressure of about 2000 tons provided to 



THE BROOKLYN-MANHATTAN DIVISION 31 

force them forward; two shields, working from Garden Place 
toward the center of the river, were operated under air pres- 
sure in water-bearing sand. The river tubes have a 3.1 per 
cent grade, and at the deepest point in the middle of the river 
the depth is about 94 feet below mean high water. 

The typical subway of reinforced concrete from Clinton 
Street to the terminus at Flatbush Avenue was constructed 
by the method already described in connection with the Man- 
hattan-Bronx Division. From Borough Hall to the terminus 
the route of the subway is directly below an elevated structure, 
which was temporarily supported by timber bracing having its 
bearing on the street surface and upon the tunnel timbers. 
Permanent support was provided by means of masonry piers 
built upon the roof of the subway structure. 

Along this portion of the route are surface electric roads 
operated by an overhead trolley on tracks of the ordinary tie 
construction. Little difficulty was experienced in taking care 
of these during the construction of the subway. Work was 
carried on day and night, the excavation being expedited by 
using flat cars on the surface trolley roads for removing the 
spoil. Spur tracks were built for this purpose and most of this 
removal was done at night. 



CHAPTER VI 

COMPRESSED AIR IN THE SUBWAY CONSTRUCTION: COST OF 
EXCAVATION IN THE NEW YORK SUBWAY 

The original plan of the general contractor on the New York 
subway work, Mr. John B. McDonald, was to install air com- 




Ingersoll-Rand Corliss Compressor Used in Subway Construction at the 
Battery Park Plant. This Compressor was one of those used in build- 
ing the Jerome Park Reservoir. 

pressing plants at convenient points along the line of construc- 
tion and to dispose of the air power to the sub-contractors. 
This project, however, was not carried out. The sub-contractors 
installed their own compressor plants, either as individuals 
or by a number of them uniting to build a plant for their own 

32 



COMPRESSED AIR IN THE SUBWAY CONSTRUCTION 33 

use. The installation and use of central air compressing plants 
to provide power for the work may be accepted as the factor 
that made possible the building of the subway within the 
specified limits of time and cost. It is to be regretted that no 
record was kept of the actual cost of operation of these plants. 
Nor were there any steam plants working under similar con- 
ditions with which comparison could be made. There can be 
no doubt, however, that the advantages of compressed air 
were a controlling influence in hastening this important work. 
To illustrate the advantages of a central air compressing plant 
over the use of scattered, direct steam driven machines, the 
following comparison is given showing the decrease in operating 
costs secured by converting the steam plants of the Gray 
Canon Quarries near Cleveland, 0., to a centralized compressed 
air plant. The table given below is a comparison of average 
daily fuel and labor charges against the power system during 
the month of April, 1903, when operating by steam and during 
the corresponding month of 1904, when operating by compressed 
air. 



1903 



1904 



Coal consumption 

Labor and attendance, 

channelers 

Labor and attendance, 

drills 

Firemen at hoists 

Firemen at pumps and 

drill boilers 

Firemen at mill, 12 -hour 

shift 

Boiler repair gang 

Locomotive repair and 

rental 

Coke for reheaters 

Total charge, labor and 

fuel 



50 tons run-of-mine 
at $2 $100.00 

16 machines at $10 160.00 

15 machines at $3 45.00 
9 men at $1.25 11.25 



15^ tons slack at 
$1.60 $ 24.80 

12 machines at $10 120.00 



9 machines at $3 27.00 



2 men at $2 
2 men at $1.25 



4.00 

2.50 
5.00 

10.00 



1. 00 



$337-75 



$172.80 



The total daily saving in labor and fuel by means of com- 
pressed air was $164.95, corresponding to a total saving in a 
year of 300 days of $49,485.00. 



34 SUBWAYS AND TUNNELS OF NEW YORK 

The reduction in the number of machines operated in 1904 
is due to the fact that a high and constant air pressure was 
always available and enabled the lesser number of machines 
to do more work than was performed by the greater number 
in 1903, when operating under the lower and fluctuating steam 
pressure. It is assumed in the table that the minor charges 
for lubrication and waste are the same. 

The coal consumption was a matter of absolute record. 
In 1903, run-of-mine coal was used, delivered to 31 boilers, and 
broken, scattered and wasted in cartage. In 1904 slack coal 
was handled, at minimum cost. 

Another fact worthy of note is that the steam plants replaced 
by the new air system were, in most cases, operating under 
conditions of average fuel and steam economy. The boilers at 
the hoists were of good tubular type, in standard brick settings 
and well housed. The channelers carried their own boilers of 
standard locomotive type. Yet even with these favorable 
conditions for fuel economy the saving in coal consumption 
has been as indicated in the table above. The tabulated com- 
parison is a statement of fact, but it fails to bring out two points 
of vital importance, viz., the output of rock, when using air, 
was greater than when using steam; and this increased output 
was secured with a force reduced by 75 men. Figuring these 
men at the average daily wage paid, the daily saving already 
shown is brought up to $275.00. 

The result is due to the fact that a full working day of ten 
hours is secured. When the throttles are opened a full working 
pressure is available and maintained throughout the working 
day. There is no delay in starting due to fluctuating boiler 
pressure. There is no labor employed in wheeling coal, in 
moving water barrels and pipe to keep pace with machines. 
There is no steam or smoke settling in the work and inter- 
fering with the hoisting. There is no water to be blown out 
or draining gangs to look after the pipes to avoid freezing. 
The working conditions are in every way improved. 

Cost of Rock Excavation in Open Cut: New York Subway. 
The results here given were secured under fair average conditions, 



COSTS OF EXCAVATION IN NEW YORK SUBWAY 35 

using air driven rock drills, loading the spoil into self-dumping 
buckets carried by cableways, and dumping into wagons. 

The cost of drilling, blasting and disposing of the spoil was, 
in mica schist, from $2.25 to $2.40 per cubic yard, varying with 
the length of haul and the depth of cut. This high cost per 
cubic yard was due to inefficient labor, to the restriction of city 
ordinances limiting the amount of explosive used at a blast, 
and to the great amount of trimming and sledging of rock. 

The average scale of wages was, for an 8-hour shift, 
as follows: 

Foremen $3.50 to $4.00 

Laborers 1.50 

Teams and drivers 4.50 

Drillers 2.75 

Drillers' helpers 1.50 

Hoist runners 3.00 

Compressor engineers 4.00 

Firemen 2.00 

Carpenters 3.50 

Timber handlers 2.00 

Smiths 2.75 

Smiths' helpers 1.50 

Water boys 75 

In the cost per cubic yard as here given allowance has been 
made for all charges, including interest and depreciation. 

The depth of excavation was from twenty-five to forty feet 
and the average width about forty feet. Laborers handled 
and loaded something less than two cubic yards per shift; this 
small performance to be accounted for by the sledging and plug- 
and-feather work required after blasting, to make the rock of 
a size that could be loaded into the buckets by hand. The cost 
of hauling about one mile was from 55 to 65 cents per cubic yard. 
The average weight of 40 per cent dynamite used per cubic 
yard was three-fifths of a pound, dynamite costing 12 h cents per 
pound. 



36 SUBWAYS AND TUNNELS OF NEW YORK 

Cost of Earth Work: New York Subway. The earth exca- 
vation in the lower part of the city was usually performed 
under the most difficult conditions. It was required that the 
street traffic should not be interfered with during the day time; 
that surface car tracks should be diverted or supported; and 
that the net-work of mains, conduits and sewers should be kept 
operating during construction. 

The cost of earth excavation under these conditions was 
from $3.50 to $3.70 per cubic yard. In places where the work 
was in sand, the cost of shoring and supporting the mains, pipes 
and conduits was 50 cents per cubic yard. In the sections 
in the upper part of the town where the traffic was less and the 
conditions more favorable, the cost varied between 75 and 95 
cents per cubic yard. This was in earth, ploughed and shoveled 
into wagons, the wagons being pulled out of the cut by power 
or snatch teams. 

Under conditions where the surface tracks required more 
support, where the mains and conduits were more numerous, 
and where the spoil was dumped at sea, the cost increased to 
$1.25 to $1.60 per cubic yard. The charge for hauling to sea 
by barge was 60 cents per wagon load, equivalent to about 30 
cents per cubic yard. The contractors were paid from $2.00 
to $2.50 per cubic yard according to the difficulties of excavation. 

Cost of Concrete : New York Subway. 

In foundations $4.50 to $4.75 per cubic yard 

Roof and side arches 7.50 to 8.00 per cubic yard 

Average cost per cubic yard in 
arches, foundations and covering 6.00 

Cost of Brick Work : New York Subway. 
In backing $10.50 to $11.00 per cubic yard 



CHAPTER VII 

THE PENNSYLVANIA RAILROAD DEVELOPMENTS IN AND NEAR 

NEW YORK CITY 

The North River Bridge Company projected the building 
of a great suspension bridge across the North or Hudson River 
to enable all of the railroads terminating on the west shore of 
the river to enter New York City at the foot of West Twenty- 
third Street. The Pennsylvania Railroad Company gave this 
project its support by agreeing to pay its pro rata share for the 
use of the bridge, but the other railroads declined to participate 
and the plan was abandoned. 

The Pennsylvania Railroad having acquired control of the 
Long Island Railroad, and having decided to establish terminal 
facilities in New York City proper, undertook the project of 
connecting New Jersey, Manhattan Island and Long Island 
by a system of tunnels. New operating conditions, resulting 
from the application of electric traction to the movement of 
heavy railroad trains, which were initiated in tunnel operation 
by the Baltimore & Ohio Railroad and subsequently studied 
and adopted by railroads in Europe, had eliminated the dif- 
ficulties of ventilation connected with steam traction through 
tunnels and also made possible the use of grades which had 
been practically prohibitive with the steam locomotive. 

Under the new plan the main line of the Pennsylvania 
Railroad connects with the tunnel system by a surface line 
beginning near Newark, N. J., which crosses the Hackensack 
Meadows, passes through Bergen Hill and under the North 
River, Manhattan Island, and East River in tunnels, to a 
large terminal yard known as Sunnyside Yard in Long Island 
City 

37 



38 



SUBWAYS AND TUNNELS OF NEW YORK 




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THE PENNSYLVANIA RAILROAD DEVELOPMENTS 39 

The estimated cost of the New York tunnel extension and 
station, including the interchange yards at Harrison, N. J., and 
Sunnyside, L. I., was $100,000,000. 

This system is essentially one for handling passenger traffic, 
but the Pennsylvania Railroad has not only the legal power 
but also the facilities for making it a through route for freight 
if desired. The requirements include handling the heaviest 
through express trains as well as the more frequent and lighter 
trains for local service. The following summary of the various 
divisions of the line will give a comprehensive idea of the general 
features of the project. 

The Meadows division includes the interchange yard at 
Harrison, near Newark, N. J., adjoining the tracks of the present 
New York division of the Pennsylvania Railroad. It also 
includes a double-track railroad across the Hackensack meadows 
to the west side of Bergen Hill, a total distance of 6.04 miles. 
The construction throughout this division is embankment and 
bridge work. 

The North River division commences at the west side of 
Bergen Hill and passes through the hill in two single-track rock 
tunnels to a large permanent shaft at Weehawken, near the 
west shore of the North River; and thence eastward a distance 
of 224 feet to the Weehawken shield chamber. It then passes 
under the North River through two cast iron, concrete-lined, 
single-track tunnels having an outside diameter of 23 feet, to a 
point under Thirty-second Street near Eleventh Avenue, in New 
York City. It continues thence through two single track tunnels 
of varying cross-section, partly constructed by the cut-and-cover 
method, to the east side of Tenth Avenue. Here it enters the 
station yard and terminates at the east building line of Ninth 
Avenue. The work in this division includes the station yard 
excavation and walls from Tenth Avenue to Ninth Avenue, 
and the retaining walls and temporary underpinning of Ninth 
Avenue. The aggregate length of line in this division is 2.76 
miles. 

The New York Terminal Station and its approaches extend 
from the east line of Tenth Avenue eastward to a point in Thirty- 



40 SUBWAYS AND TUNNELS OF NEW YORK 

second and Thirty-third streets, distant respectively 292 feet 
and 502 feet eastward from the west line of Seventh Avenue. 
This division includes also the construction of subways and 
bridges for the support of Thirty-first and Thirty-third streets 
and Seventh, Eighth and Ninth avenues. Work classified 
under this division comprises also the Terminal Building between 
Seventh and Eighth avenues; the foundations for the Post 
Office to be erected west of Eighth Avenue; the service power 
house in Thirty-first Street between Seventh and Eighth avenues; 
the power house in Long Island City; and the traction system, 
tracks, signals and miscellaneous facilities required in the phys- 
ical construction of the entire terminal railroad ready for 
operation. 

The terminal station is of steel skeleton construction with 
masonry curtain walls, all supported by a system of columns 
reaching to rock foundation. The building covers two city 
blocks and one intersecting street and has an area of about 
eight acres. It is 774 feet long, 433 feet wide, with an average 
height above the street of 69 feet and a maximum of 153 feet. 
The main waiting room is 277 by 103 feet and 150 feet high. 
The concourse is 340 feet by 210 feet in size. 

The level of the track system below the street surface varies 
from 39 to 58 feet, and is from 7 to 10 feet below mean high water 
in the harbor. This necessitated the establishing of an elaborate 
system of drainage over the entire station yard area. 

To accelerate the loading and unloading of trains, high 
platforms are constructed in the station on a level with the 
floors of the cars in order to avoid the use of car steps and to 
increase the traffic capacity of the station. Access to the 
street is gained by elevators and stairways. There are twenty- 
one standing tracks at the station and eleven passenger plat- 
forms providing 21,500 feet of platform adjacent to passenger 
trains. Within the station area, which from Tenth Avenue to 
the normal tunnel sections east of Seventh Avenue comprises 
28 acres, there is a total of about sixteen miles of track. 

The service plant for the accommodation of machinery 
for lighting, heating and ventilating the station, and for operat- 



THE PENNSYLVANIA RAILROAD DEVELOPMENTS 41 

ing the interlocking switch and signal system, is located in an 
independent building south of the station. 

The power house to supply the electrical energy for the 
operation of the tunnel lines and the Long Island Railroad 
is located in Queens Borough on property adjoining the present 
Long Island station, near the East River. As at present designed 
the dimensions of the structure are 200 by 262 feet outside. 
It accommodates six generating units of 5500 k.w. (the standard 
capacity adopted for traction work) and two units of 2500 k.w. 
for lighting. The ultimate capacity of this station when fully 
extended will be about 105,000 k.w. 

The East River division begins at the eastern limits of the 
New York station in Thirty-second and Thirty-third streets, 
including also the excavation work and retaining walls for the 
station site and yard to the track level westward to Ninth 
Avenue. It extends eastward from the station through tunnels, 
partly three-track and partly so-called twin tunnels to Second 
Avenue. Thence the line curves to the left under private 
property to the permanent shafts a short distance east of First 
Avenue. From this point four single-track, cast iron, concrete- 
lined tunnels 23 feet in outside diameter cross under the East 
River, and after passing through permanent shafts near the 
bulkhead line reach the surface in Long Island City from 3000 
to 4200 feet east of the East River. The eastern portals of these 
tunnels are in the Sunnyside yard. The total length of this 
division is 4.48 miles. 

The total length of the entire line included in the Pennsylvania 
extensions into New York City is 13.66 miles. There are 
6.78 miles of single-track tube tunnels and the average length 
of the tunnels between portals is 5.56 miles. 

In all parts of the work problems were encountered requir- 
ing for their solution large expenditures and much engineering 
skill; but many of the difficulties had been frequently met in 
previous engineering experience and the methods of overcoming 
them were well understood. Thus in the Meadows division 
a long and heavy embankment (part of which was on submerged 
meadow land) and many bridge foundations had to be con- 



42 SUBWAYS AND TUNNELS OF NEW YORK 

structed. In the Bergen Hill tunnels a very tough trap rock 
was encountered. In the tunnels under New York City the 
work was much complicated and its cost greatly increased by 
the necessity of caring for sewers, water and gas pipes, and 
foundations of adjacent buildings. Many troublesome problems 
were also met in the construction of the tunnels connecting the 
East River with the Sunnyside yard. The novel features 
of the project, however, were the great tunnels carrying the line 
under the North and East rivers. 

The maximum grade west of the terminal station occurs 
on the New York side of the North River. It is 2 per cent 
in the west-bound and 1.93 per cent in the east-bound 
tunnels. The ruling grades for the ascending traffic are 1.32 
per cent in the west-bound and 1.93 per cent' in the east-bound 
tunnels. In the tunnels east of the terminal station the ruling 
grade is 1.5 per cent for both east-bound and west-bound traffic. 
These grades would be objectionable, if not prohibitive, with 
steam locomotives under heavy traffic, but the development 
of the electric locomotive has rendered operation over these 
grades entirely practicable. 

From the junction with the Pennsylvania Railroad, near 
Harrison, N. J., to Woodside, L. I., a distance of 13.66 miles, 
there is an average of 1.5 curves per mile. The line has a total 
curvature of 230 degrees and the maximum curvature is 2 
degrees. 

The character of the material through which the subaqueous 
tunnels were constructed differed greatly in the two rivers. 
The bed of the North River at the level of the tunnels consists 
of silt, composed principally of clay, sand and water. The 
bed of the East River at the working point is made up of a great 
variety of materials, including quicksand, sand, boulders, 
gravel, clay and bed-rock. When the method of construction 
had to be decided upon for these divisions of the work there 
were no thoroughly satisfactory precedents to follow in either 
case. The gas tunnel under the East River, the partly con- 
structed Hudson tunnels under the North River, the St. Clair 
tunnel under the St. Clair River, the Blackwell and several 



THE PENNSYLVANIA RAILROAD DEVELOPMENTS 43 

other tunnels under the Thames River in London, supplied 
much useful information. 

Most of the methods proposed involved temporary struc- 
tures or the use of a floating plant in the navigable channels 
of the river. After full consideration of the subject, however, 
it was decided to adopt the shield method with compressed 
air for the construction of the sub-river tunnels. This was the 
only method recommended by the chief engineers and had the 
great advantage of conducting all operations below the bottom 
of the river, thus avoiding any obstruction of the channels. 

Experience has shown that it is much more difficult to con- 
struct tunnels in such materials as were encountered in the 
East River and on the New Jersey side of the North River than 
in the more homogeneous material which was found in the 
greater part of the North River work. During the progress 
of construction under the East River there were frequent blow- 
outs through fissures opened in the river bed; and the bottom 
of the river over the tunnel had to be blanketed continually 
with clay to check the flow of the escaping air from the shield. 

In view of the serious difficulties which is was thought might 
be encountered in the application of the shield method to the 
East River work, several other methods for the execution of 
this division received special consideration. One of these was 
the freezing process, and an extended experiment was made 
to prove its possibilities. A pilot tunnel 7+ feet in diameter 
was driven into the bed of the East River for a distance of 160 
feet. Circulating pipes were established in it and brine, at a 
very low temperature, was passed through them until the ground 
was frozen for a distance of about 15 feet around the tunnel. 
Observations were carefully made to determine the rate of 
cooling and other important points connected with the process. 
It was found, however, that the construction of the tunnels 
was progressing satisfactorily by the shield method; and as so 
much time was required to freeze the material as to make the 
freezing process of no advantage in this particular case, the 
experiment was discontinued. 

The sub-river tunnels consisted of a cast iron shell of seg- 



44 SUBWAYS AND TUNNELS OF NEW YORK 

mental bolted type with an outside diameter of 23 feet and lined 
with concrete having a normal thickness of 2 feet from the out- 
side of the shell. Through each plate of the shell there is a 
small hole, closed with a screw plug, through which grout may 
be forced into the surrounding material. Each tunnel contains 
a single track. 

A concrete bench, the upper surface of which is 1 foot below 
the axis of the tunnel, is built on each side of the track, the 
distance between the bench faces being 1 1 feet 8 inches. Within 
these benches are ducts carrying the electric cables. The 
principal object in adopting single-track tunnels instead of a 
larger two-track section was to avoid the danger of accidents 
due to the obstruction of both tracks by derailment or otherwise. 

The tunnels are just large enough to allow the passage of 
the train with perfect safety, for it was believed that with 
such an arrangement the motion of the trains would secure a 
thorough ventilation. Experience seems to justify this assump- 
tion; but in order to insure thorough ventilation under unusual 
conditions, such as the stoppage of trains in the tunnels, a com- 
plete ventilation plant is provided for each tube. Furthermore 
the rapidity and safety of construction were increased by making 
the tunnels as small as possible; since one of the difficulties in 
the shield method of tunnel driving is the difference in hydro- 
static pressure between the top and bottom of the shield, which 
increases with the diameter of the tunnel. 

The concrete lining was introduced to insure the permanency 
of the structure, to strengthen it from outward pressure and to 
guard it against injury from accidents which might occur in 
the tunnel. At points where unusual stresses were anticipated, 
as where the tubes pass from rock into soft ground, the shell is 
composed of steel instead of cast iron plates. One of the most 
important questions connected with the design of these tunnels 
was their probable stability under long, continued action of 
heavy and rapid railroad traffic. The tunnels are lighter than 
the materials which they displace when the weight of the heavy, 
live load is included. 

Some idea of the increase in passenger traffic resulting from 



THE PENNSYLVANIA KAILROAD DEVELOPMENTS 45 

the establishment of the tunnel line may be obtained by com- 
paring the proposed daily train movement from the new ter- 
minal station with the train movement at other important rail- 
road stations as given below. 

Total trains Movement 
in and out at maximum, 
for 24 hours. hour. 

Jersey City 281 29 

Broad Street, Philadelphia 538 48 

Union Station, St. Louis 462 89 

South Terminal Station, Boston 861 87 

Grand Central, New York 357 44 

Pennsylvania Station, New York 500 50 

From Proceedings Am. Soc. C.E., Sept., 1909. " The New York Tunnel Exten- 
sion of the Penn. R. R.," by Chas. W. Raymond, M. Am. Soc. C. E. 



CHAPTER VIII 

BERGEN HILL TUNNELS OF THE PENNSYLVANIA RAILROAD 

These two single-track, parallel tunnels, each 5920 feet 
in length, are on the west shore of the Hudson River, and pene- 
trate Bergen Hill, which is a dyke of trap rock forming a southern 
extension of the Hudson River Palisades. The contractors 
on this work were the John Shields Construction Company 
and William Bradley. The work was contracted for January 
20, 1906, and was completed December 31, 1908. 

Starting west from the Weehawken shaft the tunnels passed 
through a fault for a distance of 400 feet. The broken ground 
in this fault consists of decomposed, sandstone, shale, feldspar, 
calcite, etc., interspersed with masses of harder sandstone and 
baked shale, gradually merging into a compact granular sand- 
stone. The trap rock is encountered about 940 feet from the 
shaft. The full face of the tunnel is in trap rock at about 1000 
feet from the shaft and continues in this formation to the 
western portal. Sandstone and trap rock are of the Triassic 
period, the latter being classified as diabase. The character of 
the trap rock varied. In places a very hard, fine-grained trap, 
almost black, was found, having a specific gravity of 2.98 and 
weighing 186 pounds per cubic foot. In this rock the average 
time required to drill a 10-foot hole with a No. 34 " Slugger " 
drill under 90 pounds pressure was 10 hours. The remainder 
of the trap varied from this extremely hard quality, due to 
different amounts of quartz and feldspar, down to a coarse- 
grained rock resembling a light colored granite and quite hard. 

The speed of drilling the normal trap in the heading was 
approximately 20 to 25 minutes per foot as compared to 60 
minutes per foot as noted above in the harder rock. The 
larger amounts of feldspar and quartz gave a greater brittle- 

46 




SECTION NO. 12 
19'6"SPAN TWIN TUNNELS 



ION NO. 4 
rWIN TUNNELS 



NOTE:- The Sub-divisions of each Cross-seotiou are numbered in order as excavated 

Sections Cross-hutched were excavated under previous contracts. 




SECTION NO. 2 
WEEHAWKEN RIVER TUNNELS 



SECTION NO. 4 
20' SPAN TWIN TUNNELS 



fe^T"l | 5; [ jp 

SECTION NO. 1 'SECTION NO. 9 

19' SPAN TWIN TUNNELS 19' SPAN TWIN TUNNELS ELLIPTICAL ARCHES 
SINGLE BENCH (ROCK SECTION) 



General Method of Excavation Adopted in the Bergen Hill Tunnels of the Pennsylvania R.R., entering New York. 



BERGEN HILL TUNNELS 47 

ness in the latter case, and made easier drilling. The normal 
trap has a specific gravity of from 2.85 to 3.04 and weighs from 
179 to 190 pounds per cubic foot. 

These tunnels were excavated entirely by the center top 
heading method, which has found almost universal application 
in the United States. The drills used throughout the work 




SKETCH SHOWING DIVISTON OF LINING* 
FOR PURPOSES OF CONSTRUCTION. AND NAMES OF SECTIONS 

Typical Cross-section of P.R.R. Bergen Hill Tunnels 

were No. 34 Rand " Sluggers " with a 3 f -inch cylinder diameter. 
The steel used was " Black Diamond," if-inch octagon section. 
These were from 2 to 12 feet in length. The bits started with 
a diameter of 2J to 3 inches, which was held to a depth of 
about 6 feet, when it was gradually decreased to from if to 2% 
inches at the bottom of a 12-foot hole. There was an average 
of one sharpening for each foot drilled and about one-quarter 



48 SUBWAYS AND TUNNELS OF NEW YORK 

of an inch of steel was used for each sharpening. The quantity 
of steel used, lost or scrapped, was one foot for every 10 
cubic yards of rock excavated, equivalent to 1.2 inches per 
cubic yard. An " Ajax " drill sharpener was used and proved 
very satisfactory. 

On the bench rubber and cotton hose covered with woven 
marline, 3 inches in inside diameter, was used in 50-foot lengths. 
For the drills the same style of hose was used, one inch in diameter 
and in 2 5 -foot lengths; and for the steam shovels 2^-inch hose 
was used in 50-foot lengths. Hose coverings of wound marline 
and of woven marline with spiral steel wire covering were 
tried. But they were not satisfactory owing to the unwinding 
of the marline and to the bending of the steel covering. 

The average quantity of powder used was 2.9 pounds per 
cubic yard. Both 40 and 60 per cent dynamite were used, 
the latter being exclusively employed in the latter part of the 
work. The rock broke well. In sandstone the weight of pow- 
der used per cubic yard was much greater than in trap. 

In drilling the central shaft a 6-hole cut was made on the 
center line, later enlarged by making 18 holes to a depth of 
6 feet. In a 24-hour day the average advance was 4 feet. In 
the shaft the drills were run by steam until a depth of 150 feet 
had been reached, when compressed air became available. Four 
drills were used until compressed air was adopted, after which 
six were operated. 

The drills were at work 5.2 hours per 8-hour shift. They 
were actually " hitting the rock " 2.5 hours per shift. The 
average depth drilled per hour during the time of 5.2 hours 
was 2.66 feet. The average footage drilled per hour, all delays 
included, was 1.64 feet. The following figures give the estimated 
cost per drill per day : 

Drill runner, 1 at $3.50 per day $3-5° 

Helper, 1 at $2.00 per day 2.00 

Nipper, 1/5 at $1.75 per day 0.35 

Heading foreman, 1/12 at $5.00 0.42 

Walking boss, 1/50 at $7.50 per day 0.15 

Blacksmith, 1/12 at $4.00 per day 0.34 



BERGEN HILL TUNNELS 49 

Blacksmith's helper, 1/12 at $2.00 per day 0.16 

Machinist, 1/12 at $3.00 per day 0.25 

Machinist's helper, 1/24 at $1.75 per day 0.07 

Pipe fitter and helper, 1/50 at $5.00 per day 0.10 

Oil, waste, smith coal, etc 0.24 

Drill steel, 6 inches per shift 0.24 

Cost per shift $7.78 

The average footage drilled per cubic yard was 5 feet ; the num- 
ber of feet drilled per drill per shift was 10.5 to 12; the number 
of yards excavated per drill per shift was 3.5; the cost of 
drilling per yard was $2.22. In the foregoing the quantities 
paid for have been the basis of estimate; the quantities taken 
out were 10 per cent more than paid for. 

The following table gives a comparative record of the Bergen 
Hill tunnels and the Simplon tunnel. The formation in the 
Italian end of the Simplon was an antigoric gneiss, a very hard 
rock. 

Bergen Hill Simplon 

Drill set up in heading, percentage total 

elapsed time 50% 60% 

Actually drilling the rock, percentage of 

total elapsed time 50% 50% • 

Average advance per round (attack) 8.5 ft. t,.S ft. 

Average time for each attack 36 hrs. 5 hrs. 

Average advance per day of 24 hours .... 5 ft. 18 ft. 

Depth of holes 10 ft. 4.6 ft. 

Diameter of holes 2f ins. i\ ins. 

Lineal feet drilled per hour, per drill 2.7 7 

Lineal feet drilled per cubic yard 5 6 

Pounds of dynamite per cubic yard 3.4 to 5.7 8J 

Average depth drilled with one sharpening. 12 ins. 6 J ins. 

Note. From paper by W. F. Lavis, before the American Society of Civil 
Engineers, April 6, 1910. 

The conditions affecting the disposal of the muck after 
blasting were not the same at the two ends of the Bergen Hill 



50 SUBWAYS AND TUNNELS OF NEW YORK 

tunnels. On the eastern end the grade descended toward 
Weehawken, and at the western end there was an ascending 
grade. At Weehawken the mouth of the tunnels was at the 
bottom of a shaft 80 feet deep. The muck in the tunnel cars 
was hoisted by elevators to a platform at the top, from which 
it was dumped into standard gage cars and later hauled to the 
crusher or storage pile, some 500 feet distant. At the western 
end the cars were hauled directly to the surface through the 
approach cut; and the material, except that which was required 
for concrete and rock packing, was hauled from 1000 to 3000 
feet across the Hackensack Meadows. The disposal tracks 
were of 36-inch gage and were generally laid with 60-pound 
rails. 

Except for about 1000 feet in each tunnel at the Weehawken 
end, where the muck was loaded by hand, four steam shovels 
operated by compressed air were used, one in each working 
face. Three 30-ton " Vulcan " and one 38-ton " Marion " 
shovels were used. These were on a standard gage track, and 
during blasting operations were moved 300 to 500 feet back 
from the face. At Weehawken empty cars of an average load 
capacity of one cubic yard were pushed to the shovels by hand 
from the storage tracks. When loaded they were started down 
grade by the bucket and coasted to the storage track near 
the shaft. The unloaded cars were hauled back to the storage 
track by mules, one mule handling two cars. When the tunnels 
were in full working order sixty muck cars were in use, about 
evenly divided between the two tunnels. 

When mucking by hand the mucking gangs consisted of 
from 15 to 20 men. The maximum output per shift was 50 
cubic yards and the average 35 cubic yards. The maximum 
output of any of the shovels was 159 cubic yards per shift and 
the best average in any one month was 60 cubic yards per shift. 
As the shovels were generally idle for one shift out of three, 
the quantity actually handled averaged 90 cubic yards per shift 
during the shifts that the shovels were at work. These quan- 
tities are " place measurement " and equal to about twice "car 
measurement." The shovels at both ends were usually worked 



WEE HAWK 

CROSS-SECT I 




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CROSS-SECTION THROUGH T.& T. MANHOLE 

Sta.2G2+75 




PLAN 



ELEVATION 

U-BOLT ATTACHMENT FOR OVERHEAD 
CONDUCTOR POCKET 

Typical Dimensioned Cross-Sections, Be 



rUNNELS 

MANHOLES 



.This section of 10 z 10 timbering, 
in the North Tunnel extends 
from Sta.263+ 00 to 
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CROSS-SECTION THROUGH HIGH TENSION MANHOLE 
Sta.263+00 



Standard Section 
Line 



Neat line 




Hill Tunnels of the Pennsylvania R.R. 



BERGEN HILL TUNNELS 51 

with day crews — one night crew worked the shovels in either 
tunnel as occasion required. 

At the Hackensack or western end one-way dump cars were 
used having a capacity of four cubic yards. These were hauled 
by dinky locomotives, of which there were three, and later four, 
in use. To haul the cars outside to the dumps and crusher 
one 15-ton, 10 by 16-inch, Porter locomotive was used. In the 
tunnels three 12-ton, 9 by 14-inch, Vulcan locomotives were 
used. About thirty Allison dump cars were on the job, of 
which there were generally three to six undergoing repairs. 
The work was usually arranged so that the heavy mucking 
shifts alternated in the two tunnels. Two engines were then 
worked in the one tunnel and a single engine in the other tunnel. 
Generally four cars were hauled out together. 

The muck from the central shaft headings was loaded by 
hand into cars, which were then taken to a platform 20 feet 
above the surface by a double elevator and dumped into storage 
bins or wagons. 

The method by which the best results were obtained was 
as follows: A full round was blasted every thirty-six hours, 
securing an advance of 9 feet of full tunnel section. During 
the first shift of three, when the blasting had been completed 
and the lights strung, the shovel moved forward, cleaning the 
floor to the main pile of muck. The material from the blast 
was scattered from 150 to 300 feet back from the face. During 
this shift also the drillers mucked the heading and set up the 
drills, the muckers helping to carry the drills and their columns. 
During the second shift the main pile of muck was disposed of, 
leaving not more than two or three hours' work for the shovel 
on the third shift. This left nearly the whole of the third 
shift for drilling the lift holes. 

At Weehawken difficulty was encountered from the fog 
and smoke in the tunnels after blasting. This was aggravated 
on days when the barometric pressure outside was low. A 
6-foot fan, driven by an electric motor, was installed in the 
cross-passage 900 feet from the shaft (the heading being at 
that time about 300 feet in advance of this point) to force the 



52 SUBWAYS AND TUNNELS OF NEW YORK 

air from the south into the north tunnel, drawing it in at the 
mouth of the south tunnel and discharging it at the mouth of 
the north tunnel, thus insuring a circulation in both tunnels. 
The fan was moved ahead to the next cross-passage when the 
work had progressed far enough. The compressed air dis- 
charged from the drills kept the headings, as well as that part 
of the tunnel between the headings and the fan, fairly 
clear. 




mm 



Method of Ventilation, Bergen Hill Tunnels. 

The total elapsed time from starting at the Weehawken 
end to the completion of the excavation was almost exactly 
three years. The total number of days actually worked was 
940, giving an average progress of 6.26 feet per working day at 
each of the two tunnels. Omitting the central shaft headings 
this gives an average rate of progress for each working face of 
3.13 feet per day. At the Weehawken end the total number 
of days worked was 763, divided as follows: In timbered 
section, 186 days and about 426 feet, giving an average rate 
of 2.3 feet per day in each tunnel; in hard sandstone, 176 days 
and about 563 feet, at an average rate of 3.2 feet per day in each 
tunnel; in hard trap rock, 112 days and about 267 feet, giving 
an average rate of 2.4 feet per day in each tunnel; in ordinary 
trap rock, 289 days and about 13 16 feet, the average rate being 
4.55 feet per day in each tunnel. 

The best month's work was in the Hackensack end, in 
trap rock, and was as follows: May, 1907, working in the 
south tunnel from the portal to the central shaft headings, 
139 lineal feet, equivalent to about 5 feet of heading per day; 
November, 1907, enlargement of headings, 176 lineal feet, 
equivalent to 6 feet per day; April, 1908, working from the cen- 



BERGEN HILL TUNNELS 53 

tral shaft headings to the Weehawken headings in the north 
tunnel, 145 lineal feet or 5.2 feet per day. 

In the central shaft headings during April, 1907, 122 feet 
of lineal heading, averaging 3.8 cubic yards per lineal foot, 
were taken out in the south tunnel. This is equal to 5 feet 
per day for the 24 days worked. 

The best week's work at either of the main working faces, 
when the full section was being excavated in trap rock, was 
803 cubic yards, equal to 41.8 lineal feet of full section tunnel, 
or an average of 6 lineal feet of full section per day. 

The largest number of cubic yards taken out in any one week 
from one working face was 1087, equal to about 56.6 lineal 
feet of full section or an average of 8.1 lineal feet of full section 
per day. 

The largest yardage for the whole work in any one week 
was 3238 cubic yards from four working faces — two faces at the 
Weehawken end in full section and two faces at the Hackensack 
bench and enlargement. This was equivalent to 168.4 lineal 
feet of full section tunnel or an average of 6 lineal feet per day 
from each working face. 

The plant first installed at Weehawken and taken over 
by the contractor who finished the work was composed very 
largely of second-hand material. Eventually most of it had 
to be replaced. Insufficient and inefficient plant, and delay 
in installation, were largely responsible for the small progress 
made at the beginning of the work. An endeavor to continue 
the use of this plant not only caused added delay, but also 
involved a large expense. The plant installed by the original 
contractor proved inadequate to supply the air for the shovels 
and drills. The latter equipment consisted of two shovels 
requiring 1100 cubic feet per minute and 20 Rand " Slugger " 
drills using 2088 cubic feet of free air per minute. An arrange- 
ment was made with the O'Rourke Construction Company, 
then at work on the sub-river tunnels, to provide 4000 cubic 
feet of free air per minute at 100 pounds; and the old plant 
was shut down. The air compressing plant which finally sup- 
plied the air for the Bergen Hill tunnels was built by the Ingersoll- 



54 SUBWAYS AND TUNNELS OF NEW YORK 

Rand Company. The air was compressed to 40 pounds by 
low pressure machines, one being used all the time and two 
when necessary. These compressors were of the Corliss steam 
driven duplex type, with cross-compound steam cylinders and 
simple duplex air cylinders. Each unit had a capacity of nearly 
4000 cubic feet of free air per minute. This air at 40 pounds 
was delivered to an Ingersoll-Rand high pressure machine of 
the same general type, having cross-compound Corliss steam 
cylinders 14 and 26 by 36 inches, with piston inlet air cylinders 
13 J inches in diameter. This machine compressed to 100 pounds. 
The capacity of this high pressure machine taking air at atmos- 
pheric pressure was 920 cubic feet per minute at 85 r.p.m. 
Taking air at 40 pounds from the low pressure machines, and 
working at a somewhat higher speed, this compressor alone 
supplied all the air used at the Weehawken end (approximately 
4000 cubic feet per minute) from December, 1906, to November, 
1907. With very few exceptions the pressure was steadily 
maintained at from 90 to 100 pounds and there was no break- 
down of any kind. 

At the Hackensack end the old plant was also found 
inadequate and a new installation was made in another situa- 
tion, as it was found that the old site in the meadows was on 
soft ground and the vibration of passing trains caused the 
settling of foundations and the breaking of steam pipes. The 
new plant included two pairs of Stirling boilers with a total 
capacity of 2000 h.p. Eight compressors were installed, all of 
the Ingersoll-Rand straight-line steam driven type, 24 and 24 
by 30 inches, each with a rated capacity of 1250 cubic feet of 
free air per minute. Seven of these were generally worked to the 
limit of their capacity to supply the necessary air. 

The maximum requirements of air at the Hackensack or 
western end were originally estimated as follows : 

Central shaft, four headings 24 drills 

Hackensack end, two working faces 20 drills 

44 drills 



BERGEN HILL TUNNELS 55 

Cu. Ft. Free 
Air per Min. 

44 Slugger drills 4,350 

2 steam shovels 1,600 

Pumps and machine shops (estimated) .... 1,000 

4 hoisting engines, placing concrete 2,000 

4 derricks 2,000 

Total : 10,950 

The rated total capacity of the eight compressors was 10,000 
cubic feet of free air per minute. It was considered that not 
more than two-thirds of the machine equipment would be work- 
ing at the same time. The actual air requirement, therefore, 
was estimated to be about 8000 cubic feet of free air per minute, 
leaving a margin of one spare compressor for emergencies. 
The heaviest actual requirement, therefore, was approximately 
as follows: 

Cu. Ft. Free 
Air per Min. 

40 drills 3828 

2 shovels 1600 

Pumps and machine shop (estimated) 1000 

2 derricks 1000 

Total 7428 

After November, 1907, when the enlargement of the central 
shaft heading had been completed, the air requirements fell 
off to the following figures : 

Cu. Ft. Free 
Air per Min. 

32 drills 2958 

2 shovels 1600 

Pumps, etc 1000 

3 hoisting engines on concrete, each working 

one-third time 500 

2 derricks 1000 

Total 7058 



56 SUBWAYS AND TUNNELS OF NEW YORK 

The average number of drills per shift was about 25 at the 
two working faces. There were also 5 to 10 drills used for 
trimming and cleaning up for concrete, with say an average 
of 7. This made a total of 32 drills in operation. 

In lining and otherwise completing the interior of the tunnels 
the following quantities of the various materials were used, 
the figures being given per lineal foot of completed tunnel: 

Concrete 7.64 cu.yd. 

Rock packing 3.22 cu.yd. 

Paid for 1.48 cu.yd. 

Outside standard section 1.74 cu.yd. 

Iron and steel . . 44.2 lbs. 

Vitrified conduits 84.0 duct ft. 

Water proofing 13.0 sq.ft. 

Flags 3.3 sq.ft. 

The quantities of some of the main items of materials in the 
Bergen Hill tunnels are as follows: 

Excavation 263,000 cu.yd. 

Cement used (concrete and grout) . . 95,000 bbls. 

Concrete 95,000 cu.yd. 

Dynamite for blasting 600,000 lbs. 

Structural steel 50,000 lbs. 

The foregoing figures are taken from a paper by Mr. W. F. Lavis, M. Am. 
Soc. C.E., on the New York Tunnel Extension of the Pennsylvania Railroad 
Bergen Hill Tunnels in the Proceedings of the American Society of Civil 
Engineers for February, 19 10. 



CHAPTER IX 
NORTH RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

The section described in this chapter is that lying between 
Tenth Avenue, New York, and the large shaft built by the 
Pennsylvania Railroad Company at Weehawken, N. J. It 
thus comprises the tunnels passing under the North or Hudson 
Rivers. The O'Rourke Engineering and Construction Com- 
pany were the contractors. The subject will be treated in the 
following order, viz., shafts, plant and river tunnels. 

Two shafts were provided, one on the New York side and 
one on the New Jersey side. They were placed as near as possible 
to the point at which the disappearance of the rock from the 
tunnels made it necessary to start the portion of the work which 
must be driven by shields. 

The Manhattan shaft was located about ioo feet north of 
the tunnel center and there is nothing out of the ordinary about 
its construction. It was 55 feet deep, with a cross-section of 
32 by 22 feet. The amount of excavation involved, including 
drifts, was 2010 cubic yards. The shaft was lined with concrete 
reinforced with steel beams down to solid rock, the amount 
of concrete used being 209 cubic yards. The cost of the shaft 
was 33 J cents per cubic foot. The first 13 feet of depth was 
in filled, or made, ground, and below that the materials encoun- 
tered were red mica schist and granite. The total cost to the 
company was $12,943. 

The Weehawken shaft was a comparatively large piece of 
work. Its depth was 76 feet and its dimensions at the top 
were 100 by 154 feet, reducing to 56 by 116 feet at the bottom. 
The total amount of excavation was 55,315 cubic yards, com- 
posed of sand and decomposed trap and sand rock. The cost 
of excavation per cubic foot was 33.7 cents. The shaft was 

57 



58 SUBWAYS AND TUNNELS OF NEW YOKK 

lined with 9810 cubic yards of concrete with steel tie-rods in 
the rock. This shaft was started June 11, 1903, and completed 
September 1, 1904, at a total cost to the railroad of $166,163. 
It was located over the tunnels and included both of them. 
All work was carried on from these two shafts. 

The installation of the power plant on the Manhattan 
side occupied the time from May, 1904, to April, 1905. Air 
pressure was on the tunnels on the New York side on June 25, 
1005, and on the Weehawken side on the 29th of the same month. 
While the plants in both cases were almost identical local con- 
ditions necessitated some changes in arrangement. 

The main items and the cost of the separate items in one 
power house are as follows: 

3 500 h.p. Stirling water tube boilers $15,186 

2 Blake feed pumps 740 

1 Worthington surface condenser 6,539 

2 General Electric circulating pumps, electric. 5,961 

3 low pressure compressors, Ingersoll-Rand . . . 33,780 

1 high pressure compressor, Ingersoll-Rand . . . 6,665 
3 Blake hydraulic power pumps 3>°75 

2 General Electric electric generators and en- 

gines 7,626 

Total $79,572 

The following gives a summary of the total cost of one plant: 

Total cost of main items of plant $ 79,572 

Cost of four shields, appurtenances and dem- 
olition (including repairs) 105,560 

Cost of piping to drills, derricks and miscel- 
laneous plant 101,818 

Cost of installation, including preparation of 

site 39,534 

Total prime cost of one power house plant. . $324,484 

At each shaft there were three Class " F " Stirling boilers 
rated at 500 h.p. Each boiler had 5000 square feet of heating 



NORTH RIVER TUNNELS 59 

surface and 116 square feet of grate area, with independent 
smoke stacks, 54 inches in diameter and 100 feet in height above 
grate level. Shaking grates were used and firing was done 
by hand. There were four doors to each furnace. An average 
of 20 tons of buckwheat coal was used in 24 hours, at each 
plant. The average steam pressure carried was 135 pounds. 

There were two feed pumps at each plant having a free 
discharge capacity of 700 cubic feet per minute, the size being 
10 and 6 by 10 inches. 

At each plant there were three Ingersoll-Rand low pressure 
compressors used to supply air to the working chambers of 
the subaqueous shield-driven tunnels. They were also used 
on occasion to supply air to the high pressure compressors 
when the latter were hard pressed by an unusual demand for 
increased high pressure air. These machines were of a new 
design, of duplex Corliss type with cross-compound steam 
cylinders, designed to work condensing but capable of operating 
non-condensing. The air cylinders were single stage duplex. 
Steam cylinders were 14 and 30 inches in idiameter by 36 inches 
stroke. Air cylinders were 232- inches in diameter and had a 
combined capacity of 35.1 cubic feet of free air per revolution. 
While the machines were capable of running at 135 r.p.m., 
their normal speed was about 125 r.p.m., at which the free air 
capacity was 4389 cubic feet per minute or 263,340 cubic feet 
per hour. The steam pressure was 135 pounds and an air 
pressure of 50 pounds could be obtained from each compressor. 

One high pressure Ingersoll-Rand compressor of cross- 
compound Corliss steam driven type was located in each of the 
plants. The capacity was about 11 00 cubic feet of free air per 
minute when running at 85 revolutions and using atmopsheric 
air for the intake. When taking air at 30 pounds from the low 
pressure compressors the capacity was 3305 cubic feet per minute 
per machine. With a low pressure compressor running at 125 
r.p.m. it furnished enough air at 30 pounds to supply the high 
pressure compressor running at 85 r.p.m. With a high pressure 
machine delivering at 150 pounds the combined capacity of 
this arrangement was 4389 cubic feet of free air per minute. 



60 



SUBWAYS AND TUNNELS OF NEW YORK 



The air was delivered into a receiver 4 feet 6 inches in diameter 
by 12 feet high. 

There were two Worthington surface condensers at each 
plant, each with cooling surface sufficient to condense 22,500 
pounds of steam per hour, with water at 30 degrees Fahrenheit, 
maintaining a vacuum of 26 inches with the barometer at 30 
inches. Each condenser was fitted with a horizontal direct 




Interior of Weehawken Air Compressor Plant for P.R.R. North River 

Tunnels. 



acting vacuum pump. Two 8-inch centrifugal circulating 
pumps driven by 36 h.p. direct current motors, running at 220 
volts and 610 r.p.m., were placed on a nearby wharf and sup- 
plied salt water for the condensers directly from the Hudson 
River. 

To operate the tunneling shie'ds three hydraulic power pumps 
with 15-inch duplex cylinders and water rams 2-§ by 10 inches 
were installed at each power house, capable of giving a pressure 



NORTH EIVER TUNNELS 



61 



of 6000 pounds per square inch. One pump was used for each 
tunnel and the third was held in reserve. The usual working 
pressure carried was 4500 pounds. 

Electric light and power were supplied by two direct current 
generators, delivering at 240 volts through a two-wire system. 
These units were driven direct by a vertical tandem compound 
engine 10 and 20 by 14 inches, giving 150 h.p. at 250 r.p.m. 

The following is the cost of operating one power house plant 
during the period of driving the shields, excavating and metal 
lining, in a 24-hour day: 



No. 


Labor 


Rate per day 


Amount 


6 


Engineers 


$3.00 


$18.00 


6 


Firemen 


2.50 


15.OO 


2 


Oilers 


2.00 


4 OO 


2 


Laborers 


2.00 


4.00 


4 


Pumpmen 


2-75 


II .OO 


2 


Electricians 


3- 5Q 


7.00 


1 


Helper 
Total per day 


3.00 


3.00 




$62.00 




Total per 30 days .... 




$1860.00 



Supplies 



Coal 14 tons per day 


$3-25 
7.00 

•50 
.07 


$45 • 50 


Water 


7.00 


Oil, 4 gals, per day . 


2.00 


Waste, 4 lbs. per day 


.28 


Other supplies 


, 1 .00 






Total per day 


$55-78 


Total per 30 days 


$1673.00 






Cost of labor and supplies for one c 
Cost of labor and supplies for 30 da 


av 


117.78 


vs 


3533.00 







The cost of operating the power plant for 24 hours during 
the period of concrete lining was $28.00 for labor, and $61.00 
for supplies. The decrease in labor cost is due to a reduction 
in working force as but two engineers, two firemen, two pump- 



62 



SUBWAYS AND TUNNELS OF NEW YORK 



men, one foreman electrician, one electrician and one laborer 
were required. The increase in cost of supplies is due to an 
increased water consumption. 

Crushed rock for concrete was made from the trap rock 
excavated from the Bergen Hill tunnel. The crushing plant 
consisted of one No. 6 and one No. 8 Austin crusher, driven 
by a single cylinder, horizontal steam engine of 120 h.p. The 
plant was capable of crushing 225 cubic yards of stone in 10 



-- -- ,. Biver Bed 



Average Thickness of Cover 

between Biver Lines 

25'o" 




SOUTH TUNNEL NORTH TUNNEL 

Typical Cross-section of North River Tunnels Showing Relative Positions. 

hours. Stone from the pile was loaded by hand into scale 
boxes, which were lifted by two power operated derricks into 
a chute above the No. 6 crusher. From this crusher the stone 
was hoisted 60 feet by a bucket conveyor to a screen above 
the stone bin. This screen was in the form of a chute placed 
at 45 degrees and perforated with 2^-inch round holes. As 
the material passed over this chute the smaller stone dropped 



NORTH RIVER TUNNELS 63 

into the bin and the larger stone passed over into the No. 8 
crusher, from which it was carried by a second conveyor to the 
bin. The stone was loaded into dump cars of 3 cubic yards' 
capacity through a sliding door in the bottom of the stone bin, 
and was hauled by a steam dinky engine either direct to the 
Weehawken shaft or to scows for transportation to New 
York. 

The average force employed at the rock crushing plant was 
as follows: 

1 foreman at 

24 laborers at 

2 laborers at 

4 laborers at 

1 engineer at 

2 engineers at 



#3.00 




i-75 


Loading scale boxes for derricks 


i-75 


Feeding crushers. 


i-75 


To keep screens clear. 


4.00 




3 -5o 


On derricks. 



Owing to the constant breakdown of machinery, chutes, 
etc., which is inseparable from stone crushing work, a repair 
gang was always at work, consisting of either three carpenters 
or three machinists. 

The approximate cost of the crushing plant was as follows : 

Machinery $5,850 

Lumber 3,305 

Labor for erecting 3,999 



Total $13^54 

The cost of the crushed stone at Weehawken was about 
91 cents per cubic yard, made up as follows: 

Cost of stone . 22 cents 

Labor in operation of plant 31 

Plant supplies 11 

Plant depreciation 27 

Total 91 cents 

The crushed stone of the Manhattan shaft cost about $1.04 
per cubic yard, the difference of 13 cents as compared with the 
Weehawken cost being made up by the cost of transfer across 



64 SUBWAYS AND TUNNELS OF NEW YORK 

the river, amounting to 8 cents, and cost of transfer from the 
dock to the shaft, amounting to 5 cents. The stone for crush- 
ing was purchased from the contractor on the Bergen Hill 
tunnels. 

In the design of the tunneling shields for driving the tunnels 
under the river the chief points to be kept in mind were ample 
strength, easy access to the working face combined with ease 
and quickness of closing the diaphragm, and general simplicity. 
Four of these shields were used, one at each end of each of the 
tunnels. 

They were 15 feet 11^ inches long, exclusive of the hood, 
and 23 feet 6\ inches in external diameter. The outer skin 
or shell was 2| inches thick, made up of two f-inch plates with 
a f-inch plate between, butt-jointed and flush-rivetted inside 
and out. The interior framing consisted of two floors and three 
vertical partitions, forming nine compartments giving access 
to the face. They were provided with pivoted segmental doors. 
Forward of the back end of the jacks the shield was stiffened 
by an annular girder surrounding the skin, and in the space 
between the stiffeners were set 24 hydraulic rams, used to force 
the shield ahead by pressure exerted against the last erected 
ring of the metal lining. 

A cast steel segmental cutting edge was attached to the 
periphery of the forward end of the shield. The maximum 
and minimum overlap of the shield over the metal lining of the 
tunnel was 6 feet 4J inches and 2 feet, respectively. To pass 
through the varying ground before entering the true sub- 
river silt, a detachable hood in nine sections was extended 2 
feet 1 inch beyond the cutting edge and from the top down to 
the level of the upper platform. 

The weight of the structural portion of each shield was 135 
tons; of the hydraulic rams and erectors 58 tons; and of the 
complete shield 193 tons. The hydraulic apparatus was'designed 
for a maximum pressure of 5000 pounds per square inch and 
a test pressure of 6000 pounds. Each of the 24 rams was 8| 
inches in diameter by 38 inches stroke. The average pressure 
used upon them was 3500 pounds per square inch. With 




HALF SECTION A A 



Holes fo 
Poling Struts 



HALF SECTION I 



Shield Used in Driving the 




HORIZONTAL SECTION THROUGH CENTER LINE 



liver Tunnels of the Pennsylvania R.R. 



NORTH RIVER TUNNELS 



65 



a water pressure of 5000 pounds per square inch the force of 
one ram was 275,000 pounds and of the total number of 24 
rams 6,600,000 pounds or 3300 tons, giving an equivalent pres- 
sure of 15,200 pounds per square foot of face, or 105 pounds per 
square inch. The rams developed a tendency to bend under 




" - V 

Thehore segment without 
the moveable part is covered 
with 111 cement mortar instead 
of concrete. 



Cast-steel plug removed and space filled wJIh sand 
which must he thoroughly compacted* under the cover 

Cross-section of P.R.R. North River Tunnel, Showing Construction and 

Dimensions. 



the severe test of moving the shield, all closed, through the river 
silt. It is probable that a piston 10 inches in diameter would 
have been better adapted for this work than those of 8j inches 

used. 

The floors of the two platforms, of which there were eight, 



66 SUBWAYS AND TUNNELS OF NEW YORK 

formed by the divisions of the platforms by the upright fram- 
ing, could be extended forward 2 feet 9 inches in front of the 
cutting edge or 8 inches in front of the hood. This forward 
movement was produced by hydraulic jacks. The sliding 
platform could sustain a load of 7900 pounds per square foot, 
which equalled the maximum head of ground and water com- 
bined. Each sliding platform was actuated by two single- 
acting rams, 3! inches by 2 feet 9 inches. With a hydraulic 
pressure of 5000 pounds the forward force of each pair of 
rams on each platform was 96,000 pounds. As the area of 
the nose of the platform was 1060 square inches the reaction 
was 90 pounds per square inch or 13,040 pounds per square 
foot. 

Each shield was fitted with a single erector mounted on the 
rear of the diaphragm. This consisted of a box-shaped frame 
mounted on a central shaft revolving on bearings attached to 
the shield. Inside of this frame was a differential hydraulic 
plunger, 4 inches and 3 inches by 48 inches stroke. To the 
plunger head were attached two channels sliding inside the box 
frame, and to the projecting end of these the grips were attached. 
The opposite end of the box frame carried a counterweight 
which balanced about 700 pounds of the tunnel segment at a 
radius of n feet. The erector was revolved by two single- 
acting rams fixed horizontally to the back of the shield above 
the erector pivot, operating through double chains and chain 
wheels keyed to the erector shaft. With a hydraulic pressure 
of 5000 pounds the following are some of the figures connected 
with the erector: 

Weight of heaviest tunnel segment 2,584 lbs. 

Weight of erector plunger and grip 616 " 

Total weight to be handled by the erector 

ram 3,200 ' ' 

Total force in erector ram moving from cen- 
ter of shield 35>°oo ' ' 

Total force in erector ram moving toward 

center of shield 27,500 



1 ( 



^Tafl of Sh 






^^r.dde-lnta 



P$M 



■:■■■ -■-■■■■■ 



r~ 



'■'-■ 



r^r: ... 



Shield 










ir Locksj 




Inverted Rail for N 
Trailinj 
PUiforui 



SECTION AB 




I mt-i.'j. M'-y .A if J.oik 



CONCRETE 
BULKteTEAD 



01 



Id 




_J1 



I 



r 







NORTH RIVER TUNNELS 67 

Maximum net weight at 1 1 ft. radius to be 

handled by turning rams 1,884 lbs- 
Total force of each rotating ram at 5000 lbs 

per square inch 80,000 ' ' 

Load at 11 ft. radius equivalent to above. . 3,780 " 



CHAPTER X 

NORTH RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

{Continued.) 

On the New York side the shields were built inside the iron 
lining of the shield chambers, and no false work was required as 
the necessary tackle was simply slung from the iron lining. 
On the Weehawken end erecting was done in the bare rock 
excavation and false work was required. To assemble and 
rivet each shield took about two weeks, the riveting being done 
with pneumatic tools using compressed air from the tunnel 
supply. When the structural steel work was completed the 
shields, weighing 113 tons each, were jacked to grade level. 
While the hydraulic fittings were being put in, the shields were 
moved forward on a cradle built of concrete with imbedded steel 
rails, upon which the shield was driven for the distance in which 
the tunnel was in solid rock. The installation of the hydraulic 
fittings took from four to six weeks per shield and brought the 
finished weight up to 193 tons. 

When the shield was finished and in position the first two 
rings of the segmental tunnel lining were erected in the tail 
of the shield. These were firmly braced to the rock and chamber 
lining. The shield was then shoved ahead by its own jacks 
and another ring erected, and this process was continued indef- 
initely. In the description of the methods of work in the shield- 
driven tunnel which follows, the subject will be discussed in 
different sections determined by the different conditions met 
at the working face. 

In working in a full rock face, excavation so far as possible 
was done before the shields were installed. On the New York 
side about 146 feet of tunnel was completely excavated, with 
71 feet of bottom heading beyond that. At the Weehawken 

68 



NORTH RIVER TUNNELS 69 

end 58 feet of tunnel and 40 feet of heading were driven. This 
was done to avoid handling the rock through the narrow shield 
doors. Test holes were driven ahead to determine the depth 
of rock cover. At Weehawken on February 14, 1905, a blast 
broke through the rock and the mud flowed in, filling the tunnel 
for half its height for a distance of 300 feet back from the face. 

Through rock section the shield was moved upon either 
two or three rails imbedded in concrete. Where the full tunnel 
section had been excavated it was only necessary to trim off 
the small projections of rock. In the portions where a bottom 
heading only had been driven, excavation was completed just 
in front of the shield, the drilling below axis level being done 
in the heading and above that from the front sliding platforms. 
Shallow holes were drilled and spaced closely; light charges 
of powder only being used to lessen the chance of damage to 
the shield. In this work the small shield doors hampered 
operations and larger bottom openings, which would permit 
of subdivisions or of being partly closed in soft ground, would 
have been an advantage. But owing to the greater part of the 
rock having been excavated before the shields were installed 
the quantity thus handled was small. The space outside the 
lining was grouted with a one-and-one mixture of Portland 
cement and sand. Large voids were hand packed with stone 
before grouting. 

A typical working gang is given herewith. Two gangs 
were worked in each shield in 24 hours in 10-hour shifts. This 
portion of the work was done under normal air pressure. 

General 

Tunnel superintendent, \ time .... $200.00 per month 

Assistant superintendent 5.00 per day 

General foreman 5.00 

Electrician, \ time 3.50 

Electrician's helper, \ time 3.00 

Pipe fitter, \ time 3.00 

Pipe fitter's helper, \ time 2.75 



Total About $20 per shift. 



70 SUBWAYS AND TUNNELS OF NEW YORK 

Drilling 

Foreman $5.00 $ 5.00 

3 drillers 4.00 1 2.00 

3 drillers' helpers 3.00 9.00 

1 nipper 2.50 2.50 

1 water boy, \ time 2.50 . 1.25 

1 powder boy, \ time 2.75 1.38 

Cost per shift $31-13 

Mucking 

Foreman $3.50 $3.50 

8 muckers 2.75 22.00 

Cost per shift $25.50 

Erecting Iron and Driving Shields 

1 erector runner $4.00 $4.00 

3 iron workers 3.00 9.00 

Cost per shift $13.00 

Cost of shield gangs per shift $89.63 

The rate of progress obtained was 4.2 feet per day per shield 
where most of the excavation had been done beforehand and 
2.1 feet per day per shield where no advance excavation had 
been done. 

When the shields had gotten far enough away from the 
shield chambers, and before rock cover was lost, the first air- 
lock bulkhead walls were put in. These walls and their fittings 
were designed to withstand an air pressure of 50 pounds per 
square inch. They were all of concrete 10 feet thick with the 
exception of the first two, which were only 8 feet thick. Each 
had three locks capable of holding men. In addition, pipes 
were built in to give access to the cables and to pass pipes, rails, 
etc., in and out. When each tunnel had been advanced about 
1200 feet from the first wall a second wall like the first was built. 
Thus there were two of these bulkhead walls at each end of each 



NORTH RIVER TUNNELS 71 

tunnel, making 8 in all. The second bulkhead was simply an 
added safeguard to the tunnel and permitted the air pressure 
at the face to be reduced between the walls, thus lowering 
the pressure in stages. The exercise in walking between the 
bulkheads in the lower pressure was found to be beneficial to 
the health of those working in the compressed air. 

When rock cover became dangerously thin air pressures of 
from 12 to 1 8 pounds were used, this being found sufficient 
to stop the water coming from the gravel on top of the rock. 
When the surface of the rock was first penetrated the soft face 
was held by horizontal boards braced from the shield until 
the latter could be advanced. These braces were then taken 
out and replaced by others. As the amount of soft ground 
in the face increased the system of timbering was gradually 
changed to one using 2 -inch poling boards resting on top of 
the shield and supported at the face by vertical breast boards, 
which, in turn, were held by walings 6 by 6 inches braced through 
the upper doors to the iron lining and from the sliding platforms 
to the shield. In driving through this mixed ground, involving 
rock and mud, a typical working gang was as follows. In this 
part of the work three shifts of 8 hours each were employed. 

General 

J tunnel supt $300 per month $4.00 day 

Asst. supt 5.00 

General foreman 5.00 

i electrician $3.50 " 1.75 

J electrician's helper ... . 3.00 " 1.50 

i pipe fitter 3.25 " 1.63 

\ pipe fitter's helper. ... 3.00 " 1.50 

Cost per 8-hour shift. . . $20.38 

Drilling 

Foreman $5-oo day 

2 drillers $3.25 per day 6.50 

2 drillers' helpers 3.00 " 6.00 

Cost per 8-hour shift. . . $17 -5° 



72 SUBWAYS AND TUNNELS OF NEW YORK 

Timbering 
2 timbermen $2.50 per day $5.00 day 

2 timbermen's helpers . . 2.00 4.00 " 

Cost per 8-hour shift. . . $9.00 

Mucking 

Foreman $ 3.50 day 

6 muckers $2.75 per day 16.50 " 

Cost per 8-hour shift ... $20.00 

Erecting Iron and Driving Shield 
Erector runner $3-5o per day 

3 iron workers $3.00 9.00 

Cost per 8-hour shift. . . $12.50 

Total cost of labor per 8-hour shift . . 79-38 

The average rate of progress was 2.6 ft. per day. 

Tunneling in a full face of sand and gravel was encountered 
only at Weehawken, and two systems of timbering were used. 
In the first the ground was excavated 2\ feet ahead of the 
cutting edge, the roof being held by longitudinal poling boards 
resting on the outside of the shield skin at their back ends, and 
on vertical breast boards at the forward ends. When the 
upper part of the face was dry it was held by vertical breast 
boards from the sliding platforms and through the shield doors 
to cross timbers in the tunnel. The lower part, which was 
always wet, was held by horizontal breast boards braced through 
the lower shield pockets to cross timbers in the tunnel. 

As soon as the rock surface was penetrated, and the sand 
and gravel encountered, the escape of air was enormously 
increased. It was found impossible to maintain the required 
pressure even with the three compressors working to the limit 
of their capacity, each compressing 4400 cubic feet of free air 
per minute or 13,200 cubic feet in all. 

To decrease this leakage of air a large quantity of straw 
and clay was used in front of the breasting. This diminished 



NORTH RIVER TUNNELS 



73 



the loss of air, but a large quantity still escaped through the 
joints of the iron lining, so that these had to be plastered with 
Portland cement. Even then the loss was too great and it 
was necessary to shut down one tunnel and deliver all the air 
to the other. This allowed a pressure of 10 pounds to be 
maintained which, though less than the hydraulic head, was 
sufficient to permit progress to be made. The timbered face 




Interior of Shield in P.R.R. North River Tunnel, Showing Silt Entering 

Through One Open Door. 



was never grouted, for though this would have reduced the 
loss of air, it would have cut down the rate of progress very much. 
The abnormally increased demand upon the air compres- 
sors to supply the necessary air to maintain the pressure in 
the tunnel subjected the machines to a most severe and extended 
test of reliability under conditions involving extreme speed and 
greatly augmented load. A breakdown would have meant 
the loss of the working face. This extreme condition was 



74 SUBWAYS AND TUNNELS OF NEW YORK 

maintained until the silt, which lay above the sand and gravel, 
showed in the roof, when the escape of air was immediately 
reduced, and it became possible to work the two faces simulta- 
neously. 

In driving these faces a typical gang for an 8-hour shift 
was as follows: 

General 

J General supt $300.00 per month .... $4.00 per day 

Assistant supt 5.00 

General foreman 5.00 

\ electrician and helper $3.50 and $3.00. .. . 3.25 

\ pipe fitter and helper 3.25 and 3.00 3.13 



i c 
( I 



Cost per 8-hour shift $20.38 ' ' 

Timbering 

3 timbermen '. . . . $2.50 $7.50 per day 

3 timbermen's helpers 2.00 6.00 



Cost per 8-hour shift $13.50 

Mucking 

Foreman $3.50 

6 muckers $2.75 16.50 



Cost per 8-hour shift $20.00 

Erecting Iron and Driving Shield 

Erector runner $3-25 

Foreman 4.00 

4 ironworkers $3.00 12.00 



Cost per 8-hour shift $19.25 

Total cost of labor 8-hour shift $73- I 3 

The average rate of advance in sand and gravel was 5.1 
feet per day for each shield. As soon as the silt was encoun- 
tered in the upper part of the face the speed increased to 7 
feet per day per shield. 



NORTH RIVER TUNNELS 75 

In passing under the river wall at Weehawken, where the 
bulkhead consisted only of a crib-work supported on piles, 
the latter obstructed the advance of the shield but were easily 
cut out. On the New York side the conditions were not so 
favorable. Here the heavy masonry bulkhead was supported 
on piles and rip-rap. The top of the shield came about 6 feet 
above the bottom of the rip-rap and the open spaces between 
the stones allowed a free flow of water directly from the river. 
As soon as the cutting edge entered the rip-rap there was a 
blowout, the air escaping freely to the ground surface behind 
the bulkhead and to the river in front of it. Clay puddle or 
mud, made from the excavated silt, was used in large quantities 
to fill the voids between the stones in the working face. The 
excavation of this rip-rap was carried on by the removal of 
one stone at a time, the spaces between the newly exposed stone 
being immediately plugged with mud. When the shield had 
advanced its own length in the rip-rap another place for the 
escape of air was exposed at its rear end. This leakage was 
stopped with mud and cement sacks at the forward end of the 
last ring of the tunnel. 

As long as the shield was stationary it was possible, by 
using these methods and by exercising care, to prevent the 
excessive loss of air, but while the shield was being shoved 
ahead the difficulties were much increased, as the movement 
of the shield displaced the bags and mud as fast as they were 
placed. It was only by shoving slowly and having a large 
number of men looking out for leaks and stopping them that 
excessive air loss could be avoided. 

In erecting the iron lining, as a segment was placed in 
position it was necessary to clean off the forward surface of 
the previous ring and the adjacent portion of the tail of the 
shield. This was always accompanied by a slight blow and for 
some time the air pressure in the tunnel dropped from 25 to 
20 pounds. In other words, every time a segment was placed 
the air pressure dropped from greater than the balancing pres- 
sure to less; and on two occasions the blow became so great, 
and the tunnel pressure was so much reduced, that the water 



76 SUBWAYS AND TUNNELS OF NEW YORK 

from the river rushed in and was not stopped until it had risen 
about 4 feet in the tunnel invert. On such occasions the sur- 
face of the river was greatly disturbed, often rising more than 
20 feet in the air in the form of a geyser. A large quantity 
of grout (about 2500 barrels of cement and a similar amount 
of sand in the north tunnel, and 1000 barrels in the south tunnel) 
was used at this point. It was forced through the tunnel lin- 
ing immediately behind the shield, greatly reducing the loss 
of air and binding the rip-rap together. 

When the shield had traveled 25 feet through the rip-rap 
the piles supporting the bulkhead were met. One hundred 
of these, spaced on three-foot centers, were cut out of the path 
of the shield in a distance of 35 feet. In passing through the 
piling no timbering was done and the piles supported the face 
effectively. 

When the river line had been passed the blow still continued, 
and as there was no heavy ground above the tunnel the light 
silt was carried away into the water by the escaping air. At 
one time the cover over the crown of the tunnel was reduced 
to such an extent that for a distance of 30 feet there was 
less than 10 feet of very soft silt overlying and in some places 
none at all. The shield was stopped and the air pressure 
reduced to less than the balancing pressure. The blow then 
stopped and about 28,000 cement bags filled with mud were 
dumped into the hole. They were then weighted down with 
rip-rap. This sealed the blowout and the work was continued 
without further disturbance from this source. The working 
force employed here was similar to that employed in the sand 
and gravel sections. 



CHAPTER XI 

NORTH RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

{Continued.) 

In the North River tunnels, between Tenth Avenue and the 
large shaft at Weehawken, N. J., Ingersoll-Rand drills, sizes 
A-86, C-24, E-24 and F-24, were used. While the air pressure 
at the power house was 100 pounds, the effective pressure at the 
drills was only 80 pounds. The drill steel used was ij to if- 
inches, octagon. The holes were started with a 3J-inch diame- 
ter and bottomed at 2f-inch diameter at a depth of 10 feet. 
The powder used on the New York side, because of the prox- 
imity of buildings and lack of heavy rock cover, was 40 per 
cent for cite. The holes were closely spaced and light charges 
of explosive used. 

The amount of excavation done was 1 1 per cent greater 
than that paid for. For a period covering five months and 
12,900 cubic yards of excavation the record of drilling, and 
amount of powder used per cubic yard of excavation, were 
as follows: 





Feet of hole drilled per 
cu. yd. of excavation. 


Pounds of powder used per 
cu. yd. of excavation. 


Portion of excavation. 


15' 14" 

Span 
Twin T. 


19' 6" 

Span 

Twin T. 


24' 6" 

Span 

Twin T. 


IS' 4" 


19' 6" 


24' 6" 


Wall plate heading (1) . . . 
Total heading 


13.OO 

7.87 

5-97 
9.82 


10.97 

8.17 

6.15 
15.96 


10.97 
7.81 

7-56 
18.10 


3-77 
2.31 
0.94 
1.84 


2.85 
2.02 

0-93 
2.49 


2.85 
1.78 


Bench and raker bench (1) 
Trench (i) 


1 13 
2-73 




Average for section (1) . . . 


6.69 


7-43 


8-95 


1.28 


1.30 


i-45 




.82 


7.27 


8-95 


1.22 


1.24 


1 . 27 



77 



78 



SUBWAYS AND TUNNELS OF NEW YORK 



In the foregoing table the items marked (i) give the figures 
from a typical cross-section; the item marked (2) gives the 
actual amount of drilling done and powder used per cubic 
yard for the whole period of five months. But as this included 
280 feet of heading and only 220 feet of bench, the average 
figures (especially for explosives) are too low. 

The following figures cover the cost of drilling and blasting 
in the rock tunnel excavation under Thirty-second Street, east 
of the cut-and-cover section. They cover five months of time 
and 11,649 cubic yards of material paid for. The total amount 
of drilling done was 86,749 feet in 3206 drill shifts of 10 hours 
each. The average footage of hole per man per hour was 3.02 
in the heading and 2.71 on the bench. The cost of labor only 
for drilling and sharpening steels was $25,283, equivalent to 
29 cents per lineal foot or $2.17 per cubic yard paid for. The 
total amount of powder used wab 14,444 pounds, representing 
a cost of 14 cents per cubic yard, with dynamite at n cents 
per pound. The table below gives an analysis of the drilling 
operations : 



Setting up 

Drilling 

Necessary delay 

Unnecessary delay . . . 
Taking down machine 
Loading and firing . . . 

Total drilling 

Mucking 



Total 

Feet drilled per shift 

Feet drilled per working hour 



One heading. 



Quartz. 



Hrs. M 
O.38 

4-52 
1 .40 



O.05 
O.04 
7.19 
2 .41 



Hard 
mica 
schist. 



Hrs. M. 
O.I5 
8.0 

1-45 



1 .00 



IO.OO 

22.00 

2.86 



10.00 

42.00 

4.20 



Bench. 



Quartz. 



Hrs. M. 
I.23 

5-57 
2.23 

o-i5 
o-5 
0.07 
10. o 



10.00 
25-9 
2-59 



Mica 

schist 

medium. 



Hrs. M 
I -IO 
6.08 

I-50 
O.I2 
O.07 
O.07 

9-34 
0.26 



10.00 

22. 22 

2.32 



Center trench. 



Mica schist. 



Soft. 



Hrs. M. 
1-58 
5-53 
*-33 
0.06 
0.12 
0.30 
9.12 
0.48 



10.00 

22.00 

2-39 



Medium. 



Hrs. M. 
I .IO 
6.40 
1. 17 
O.IO 

0.20 

0.23 

10.00 



10.00 
26.44 

2 .64 



NORTH RIVER TUNNELS 



79 



The foregoing figures are the result of 67 observations. 
It was found that the average time and percentage per 10-hour 
shift for each operation were as follows: 



Setting up 1 hr. 

Drilling 5 

Necessary delay 1 

Unnecessary delay o 

Taking down machine . . . . o 

Loading and firing o 

Total drilling 9 

Mucking o 



While the shield chambers were being excavated bottom 
headings were run along the lines of the river tunnels, and 
continued until the lack of rock cover prevented their being 
driven further. The typical working force in the shield cham- 
bers was as follows: 



ir. 8 min. 


or 1 1.3 


" 58 " 


59-7 


" 53 " 


19.9 


" 07 " 


1.1 


09 


i-5 


" 12 " 


2 


" 27 " 


94-5 


" 33 " 


5-5 



Drilling and Blasting — Ten-hour Shifts 



1 foreman at $3.50 

6 drillers " 3.00 

6 drillers' helpers " 2.00 

1 blacksmith ' ' 3.50 

1 smith's helper " 2.25 

1 powder man " 2.00 

1 water boy " 2.00 

1 nipper ' ' 2.00 

1 machinist ' ' 3.00 

1 machinist's helper " 1.80 



Mucking 



1 foreman at $3.00 

16 muckers ' ' 2.00 



S3. 50 
18.00 
12.00 

3.50 
2.25 

2.00 

2.00 

2.00 

3.00 

1.80 

$50.05 



$3-oo 
32.00 



$35.00 



80 SUBWAYS AND TUNNELS OF NEW YORK 

ANALYSIS OF COST OF DRILLING 





Cost per foot of hole drilled. 


Cost per drill shift. 


Item of cost. 


I5'4" 


io'6" 


,,„ Aver- 
2 4'6" age. 


I5'4" 


io'6" 


24'6" 


Aver- 
age. 


Drilling labor 

Sharpening 


$0.25 
O.02 

0.007 
0.002 

O.05 


$0.28 
O.02 

O.O07 
O.02 

O.04 


$0.31 
O.OI 

0.006 
0.02 

0.07 


$0.28 

0.016 

0.007 
0.02 

0.07 


$6.95 
o.53 

0.19 
0.61 

i-39 


$ 7-75 
0.42 

0. 20 
o-59 

1.86 


$ 7-6o 
o.34 

0.15 
0.42 

1 .67 


$7-45 
0.43 


Drill steel (5" per drill 
shift) 


0. 19 
o.54 

1.82 


Drill repairs 

High pressure air 
(estimated) 


Totals 


0-35 


O.38 


0.41 


0.38c 0.67 


10.82 


10.18 


10.43 






1 



COST OF EXCAVATION OF LAND TUNNELS, IN DOLLARS PER CUBIC 

YARD 



Manhattan. 



Weehawken. 



Total yardage 

and average 

cost. 



Cubic yards excavated 

Labor: 

Surface transport 

Drilling and blasting 

Mucking 

Timbering 

Total labor 

Material : 

Drilling 

Blasting 

Timber 

Total material . 

Plant running 

Surface labor, repairs and main- 
tenance 

Field office administration 

Total field charges 

Chief office administration 

Plant depreciation 

Street and building repairs 

Total average cost per cubic 
yard 



42289 

$0.49 

2-37 
2.49 
0.87 

$6.22 



35o.i5 
o. 21 
o.39 

So. 75 

$0.76 

015 
I 05 

$8.96 

0.34 
0.66 

o. 27 



8311 

$0.87 

i-55 

2.08 
0.18 

$4.68 



#0.15 
o. 21 
0.20 

$0.56 

$0.65 

0.08 
1. 18 

$7-i5 
0.38 
1 .01 



51600 

$0.55 
2.24 
2.42 
0.76 

$5-97 



&0.15 
0.21 
0.36 

^0.72 

50.74 

o. 14 
1.07 

58.6 4 

0.34 
0.72 
0.23 



>io. 23 



•54 



$9-93 



NORTH RIVER TUNNELS 81 

In working in the shield chambers in a full face of rock as 
much as possible of the rock excavation was done before the 
shields were installed in order to avoid handling the rock 
through the narrow shield doors. The typical working gang 
in the shields, of which there were two gangs per shield per 
24 hours working in two 10-hour shifts, was as follows: 

General 

\ tunnel supt at $200.00 per month 

1 assistant tunnel supt " 5.00 per day 

1 general foreman ' ( 5.00 

\ electrician ' ' 3.50 

\ electrician's helper " 3.00 

J pipe fitter " 3.00 

J pipe fitter's helper " 2.75 

Drilling 

1 foreman at $5.00 per day 

3 drillers " 4.00 

3 drillers' helpers " 3.00 

1 nipper ' ' 2.50 

J water boy " 2.50 

i powder boy " 2.75 

Mucking 

1 foreman at $3.50 per day 

8 muckers " 2.75 ' ' 

The duties of these gangs were as follows: The tunnel 
superintendent looked after both shifts of one shield; the 
assistant or walking boss had charge of all work in the tunnel 
in one shift; the general foreman had charge of the labor at the 
face; the electrician looked after repairs, extensions of the 
cables and lamp renewals; the pipe fitters worked in both 
tunnels, repairing the leaks in pipes between the power house 
and working faces, extending the pipe lines and attending to 
shield repairs; in the latter work the erector runner helped. 
The drillers stuck to their own jobs, which were not subject to 



82 SUBWAYS AND TUNNELS OF NEW YORK 

interruption as long as the bottom headings lasted. One water 
boy and one powder boy served two tunnels. The muckers 
helped the iron men put up the rings of the casing, as well as 
looking after their own work in cleaning out the face. The 
rate of progress obtained was 4.2 feet per day per shield where 
most of the excavation had been done beforehand; and 2.1 feet 
per day per shield where no previous work had been done. 

When the rock, gravel and hard-pan gave place to a full 
face of silt, the timber was removed, all the shield doors were 
opened, and the shield was shoved forward into the ground 
without any excavation being done by hand ahead of the 
diaphragms. As the shield advanced the silt was simply forced 
through the open doors into the tunnel. After the work had 
progressed in this way for some time, taking in about 90 per 
cent of the full volume of the tunnel excavation per foot of 
advance, the air pressure was raised from 20 to 22 pounds. 
As a result the silt in the face got harder and flowed less readily 
through the shield doors; and the amount taken in fell to about 
65 per cent of the full volume. As this mode of operation 
caused a disturbance of the surface the air pressure was lowered 
to 16 pounds, when the muck became softer and the full volume 
of excavation was taken in. The pressure was later raised to 
20 pounds. 

The forcing of the shield through the silt resulted in raising 
the bed of the river in an amount depending on the quantity 
of material brought into the shield. If the whole volume of 
excavation was being brought in, the surface of the river bed 
was not affected. When about 50 per cent of the whole volume 
was being taken in the river bed raised about 3 feet; and when 
the shield was being driven blind the bed raised about 7 feet. 
The opening of doors in the shield was regulated to take in the 
minimum quantity of muck and cause no surface disturbance. 
In the north Manhattan tunnel all the doors were usually 
open; in the south tunnel five or six of the nine doors were 
generally open. 

1 From the paper by B. H. M. Hewett and W. L. Brown, before the American 
Society of Civil Engineers, June, 1910. 



NORTH RIVER TUNNELS 83 

As soon as the south shield had passed the river bulkhead 
at Weehawken the silt was found to be much softer than behind 
the wall. It was like a fluid in many of its properties and this 
fluidity could be varied by changing the air pressure in the 
shield chamber. When the air pressure was equal to the 
weight of the overlying water and silt, the silt stiffened to about 
the consistency of a very soft clay. When] the pressure was 
reduced to 12 or 15 pounds it became sufficiently fluid to flow 
through a ij-inch grout hole at a rate running up as high as 
50 gallons per minute. This was a condition which had been 
looked forward to by the contractor and it was anticipated that 
the shield doors could be closed and the shield driven across 
the river without taking in a shovelful of muck. This had been 
done in driving the Hudson and Manhattan Railroad Company's 
tunnels between Hoboken and New York City, but when the 
doors were all closed and the shield shoved forward the tunnel 
immediately began to rise in spite of the heaviest downward 
lead which the clearance at the back of the shield would permit. 

The pressure caused by the shield displacing the ground 
as it advanced caused the iron tunnel lining to rise about 2 
inches and it became distorted, the horizontal diameter decreas- 
ing and the vertical diameter increasing by as much as ii inches. 
The shield was stopped and the hood removed as it was thought 
that the latter was producing these effects. Driving was then 
resumed, but the same troubles continued and it was not 
found possible to keep to grade. 

By opening the doors and taking in a portion of the material 
these difficulties were overcome. It was found that the level 
of the shield could be regulated by varying the proportion of 
silt admitted through the doors. This quantity ranged from 
none at all to the full volume displaced and averaged about 
33 per cent. The muck flowed into the tunnel in a thick stream, 
and by regulating the advance of the shield the flow was pro- 
portioned to the time which was required to load it into cars. 
In driving through silt the typical gang per shift of eight hours 
per shield was as follows: 



i i 
1 1 
t ( 
i I 
( c 
I ( 



84 SUBWAYS AND TUNNELS OF NEW YOKK 

General 

J tunnel supt. at $300 per month $4.00 per day 

Asst. supt 6.00 

General foreman 5.00 

Foreman 4.00 

\ electrician and helper, $3.50 and 3.00 3.25 

2 pipe fitters, $3.50 7.00 

2 pipe fitters' helpers, $3.25 6.50 

Cost per 8-hour shift . . 35-75 

Mucking 

Foreman $4.00 per day 

6 muckers, $3.00 18.00 

Cost per 8-hour shift $22.00 

Erecting Iron and Driving Shield 

Foreman $4.00 per day 

Erector runner 3.50 

4 iron workers, $3.00 12.00 

3 laborers, $3.00 9.00 

Cost per 8-hour shift $28.50 

The total cost of labor per 8 -hour shift was $85.75. Three 
shifts of 8 hours each were worked under an average air 
pressure of 25 pounds. The rate of progress in the silt under 
the river was 2§ feet (the width of a ring) in every 3 hours and 
21 minutes or about one foot in 1 hour and 20 minutes. This 
was exclusive of the time during which work was suspended. 
The average daily advance, including all delays, was 10.8 feet 
per day. 

The junction of the shields under the river was made as 
follows: When the two shields of one tunnel, which had been 
driven from opposite sides of the river, approached within 
10 feet of each other the shields were stopped and a 10-inch pipe 
was driven between them in order to make a final check on lines 



NORTH RIVER TUNNELS 85 

and levels. The first traffic established was the passage of a 
box of cigars through this pipe. 

One shield was then started up with all doors closed while 
the doors on the stationary shield ahead were opened so that 
the muck driven forward by the moving shield was taken in 
through the doors of the stationary shield. This was con- 
tinued until the cutting edges met. All doors in both shields 
were then opened and the shields mucked out. The cutting 
edges were removed and the shields advanced till their outer 
skins met. The interior framing and everything except the 
outer skin of the shields was removed. The iron lining was 
then built up inside of the skins, concreted and grouted outside. 

The single erector attached to the center of the shield was 
capable of erecting the iron lining as fast as it could be brought 
into the tunnel. The individual segments varied in weight 
from 2060 to 2580 pounds. The average time spent in erect- 
ing and bolting up for the whole length of the tube tunnels 
was 2 hours and 15 minutes per ring. Each ring was 2 feet 
6 inches in width by 23 feet outside diameter. 

After the metal lining had been built completely across the 
river in both tunnels the work of making it water-tight was 
taken up. This consisted in forming a rust joint between the 
plates with a mixture of sal-ammoniac and iron borings, and 
in taking out each bolt and placing around the shank under 
the washer at each end a grummet made of yarn soaked in red 
lead. Before caulking the joints were cleaned. The usual 
mixture for the joints was 2 pounds of sal-ammoniac, 1 pound 
of sulphur and 250 pounds of iron filings or borings. Air 
hammers were used with advantage in caulking this mixture 
into the joints. 

In putting in the concrete fining in the under-river tunnels 
the mixture (proportions 1 to 2§ to 5) was turned over for 
about 1^ minutes or 20 revolutions in No. 6 Ransome mixers. 
A 4-bag batch consisted of one 380-lb. barrel of cement, 8.75 
cubic feet of sand and 17.5 cubic feet of stone. The average 
quantity of water used per batch was 25 U.S. gallons. Run- 
of-crusher trap rock with the largest stones of a size which 



86 SUBWAYS AND TUNNELS OF NEW YORK 

would pass a 2^-inch screen was generally used. The average 
resulting volume from each batch was 0.808 cubic yard. The 
force employed in mixing concrete per 10-hour shift was as 
follows : 

Manhattan side: 

Foreman $3.00 per shift 

4 men on sand and stone cars at $ 1 . 7 5 . . . 7 .00 
4 men handling cement at 1.75 .. . 7.00 

2 men dumping mixers at 1.75. . . 3.50 



1 ( 



c c 



( c 

I ( 



Labor per shift . . . . $20.00 

Weehawken side: 

Foreman $3.00 per shift 

2 men hauling cement at $1.75 3.50 

2 men dumping mixers at 1.75 3.50 

Cost of labor per 10-hour shift $10.00 

The average quantity of concrete mixed per 10-hour shift 
was about 117 batches or 90 cubic yards. The maximum 
output of one of the mixers was 168 batches or 129 cubic yards 
in a 10-hour shift. The average force per shift for transporta- 
tion in two tunnels while building two arches, two inverts and 
two duct benches consisted of two foremen, twenty-eight 
laborers, two switchmen and four hoisting engineers. The 
labor cost of this gang was $71 per shift. 

The average time required to lay a 30-foot length of invert 
was 7 hours, but two spade men remained for an hour extra, 
smoothing off. The typical working force used in placing 
concrete in the inverts was as follows: 

Foreman $3-25 per shift 

2 spaders, $2.00 4.00 

9 laborers, $1.75 15.75 

Total cost per shift $23.00 



l c 



NORTH RIVER TUNNELS 87 

The following force, with the wages listed, was used in 
cutting the forms for the concrete laying: 

Foreman $4.50 per shift 

5 carpenters, $3.25 16.25 ' ' 

6 carpenter's helpers, $2.25 !3-5o 



i 1 



Total cost per shift. . . . $34.25 

The average time required to erect a form was 2 hours, 
one carpenter and one helper remaining until the concrete was 
finished. With the same force as used in laying the concrete 
in inverts the concrete duct bench was laid at a rate of 35 feet 
in 6 hours. An average gang for a 20-foot length of arch was 
one foreman, two spaders and ten laborers, at a total labor 
cost of $21 per shift. 

Two 20-foot lengths of arch were grouted at one time, an 
average of three-quarters of a barrel of cement and three-quarters 
of a barrel of sand being used per lineal foot of tunnel. The 
average amount put in by one machine per shift was 15 barrels 
and the average length grouted was 20 feet. The typical work- 
ing force on this work was as follows: 

Foreman $3-75 P er shift 

Laborer running grout machine 2.00 

2 laborers handling cement and sand. . 1.75 
1 laborer tending valves and pipes. ... 1.75 



C ( 

I c 
I c 



Total labor per shift $9.25 

After the grouting was finished the arches were rubbed 
down with wire brushes to remove the discoloration and the 
rough places at the junction of adjoining lengths were bush 
hammered. 

The leakage after the concrete lining was in was found to 
be from 0.05 to 0.06 gallon per lineal foot of tunnel per 24 
hours, which compares favorably with the records of other 
lined tunnels. 

The air pressure carried during the progress of the sub- 
river work varied from 17 to 27 pounds per square inch. Behind 



88 SUBWAYS AND TUNNELS OF NEW YORK 

the river line it averaged 17 pounds and was generally kept 
about equal to the water head at the crown of the tunnel. Under 
the river the pressure averaged 26 pounds per square inch. 
In silt the pressure was much lower than the hydrostatic head 
at the crown, but if it became necessary to excavate ahead 
of the shields the air pressure required was about equal to 
the weight of the overlying material, water and silt. The silt, 
which weighed from 97 to 106 pounds per cubic foot, with an 
average of 100 pounds, acted like a fluid. The compressor 
plant was found to be ample for all requirements, except when 
passing the gravel section at Weehawken. 

The quantity of free air per man per hour was in general 
between 1500 and 5000 cubic feet. When there was an excessive 
escape through open gravel the supply for a time reached 
10,000 cubic feet per hour per man. For more than half of the 
time working in silt the supply was between 3000 and 4000 
cubic feet. But when it seemed evident that any quantity 
beyond 2000 cubic feet had no beneficial effect on the health 
of the workers no attempt was made to deliver more. On 
two distinct occasions for two consecutive weeks it ran as low 
as 1000 cubic feet per man per hour without any increase in the 
number of cases of bends. 

The amount of CO2 in the air was also measured daily, 
as the specifications covering the work called for not more 
than one part of CO2 per 1000 parts of air. The average 
ranged between 0.8 and 1.5 parts per 1000. In exceptional 
cases it fell as low as 0.3 and rose as high as 4.0. The temperature 
of the air in the tunnels usually ranged from 55 to 60 degrees 
Fahrenheit, which was the temperature of the surrounding 
silt, but when grouting was being extensively done in long 
sections of the tunnel in rock, the temperature varied from 
85 to no degrees Fahrenheit. 

Note. — From paper by B. H. M. Hewett and W.L. Brown before the 
American Society of Civil Engineers, April, 1910. 

Various types of screw piles were sunk and tests made not 
only of the dead load carrying capacity, but also as to their 
behavior under the addition of impact. It was found that 



NORTH RIVER TUNNELS 89 

screw piles could be sunk to hard ground and would carry the 
required load. A screw pile having a shaft 30 inches in diameter 
and a blade 5 feet in diameter was loaded to 600,000 pounds, 
with the result that for a month (the duration of this loaded 
test) there was no subsidence. 

After the iron tunnel lining had been constructed across 
the river, tests were made of two types of support. One was 
a screw pile 29^ inches in diameter with a blade 4 feet 8 inches 
in diameter; and the other was a wrought iron pipe 16 inches 
in diameter. Tests were made not only for their carrying 
capacity, but also for their value as anchorages. It was found 
that the screw pile was more satisfactory in every way. It 
could be put down much more rapidly, was more easily main- 
tained in a vertical position, and as a support for the track 
could carry satisfactorily any load which could be placed upon 
it. The 16-inch pipe did not prove efficient either as a carrier 
or as an anchorage. 

After the shields had met and the iron lining had been 
joined, various experiments and tests were made in the tunnel. 
Screw piles and the pipes previously referred to were inserted 
through the bore segments in the bottom of the tunnel. Thor- 
ough tests were made with these, levels were observed in the 
tunnels during construction and placing of the concrete lining, 
an examination was conducted of the tunnels of the Hudson 
and Manhattan Railroad Company under traffic, and the result 
was the decision not to install the screw piles. The tubes, 
however, were reinforced longitudinally by twisted steel rods 
in the invert and roof, and by transverse rods where there was 
a superincumbent load on the tunnels on the New York side. 
Where they emerge from the rock and pass into soft rock the 
metal shell is of cast steel instead of cast iron. 

There was considerable subsidence in the tunnels during 
construction and lining amounting to an average of 0.34 feet 
between the bulkhead lines. This settlement has been constantly 
decreasing since construction and appears to have been due 
almost entirely to the disturbances of the surrounding materials 
while the work was being carried on. The silt weighs about 



90 SUBWAYS AND TUNNELS OF NEW YORK 

ioo pounds per cubic foot and contains about 38 per cent 
water, this being the average of a number of samples taken 
from the shield door which varied in weight from 93 to 109 
pounds per cubic foot. It was found that whenever this material 
was disturbed outside the tunnels a displacement of the tubes 
followed. The tubes as noted have been lined with concrete 
reinforced with steel rods; and prior to the placing of the con- 
crete the joints were caulked, the bolts grummeted and the 
tunnels rendered practically water-tight. The present quan- 
tity of water which must be disposed of does not exceed 300 
gallons per twenty-four hours in each tunnel 6100 feet long. 
The quantities of some of the main items in the North 
River tunnels are as follows: 

Excavation, in cubic yards 238,995 

Cast metal used in tunnels, tons 64,265 

Steel bolts used, tons 3,606 

Cement used (concrete and grout) barrels. . . 145,500 

Concrete, cubic yards : 75, 400 

Dynamite for blasting, pounds 100,400 

Brickwork, cubic yards 4>98° 

Structural steel (including Pier 72), pounds. 3,141,000 



CHAPTER XII 

EXCAVATION FOR THE TERMINAL STATION OF THE PENN- 
SYLVANIA RAILROAD 

The site of the Pennsylvania Terminal Station in New York 
City is between Tenth and Seventh Avenues and Thirty-first 
and Thirty- third Streets; it includes an area of about twenty- 
eight acres. 

The principal contract was with the New York Contracting 
and Trucking Company, which was later assigned by that com- 
pany to the New York Contracting Company, Pennsylvania Ter- 
minal, for the performance of the following divisions of work. 

Excavation for, and construction of, the retaining walls 
in Seventh Avenue and Thirty-first Street, Ninth Avenue and 
Thirty- third Street; excavation over the entire area enclosed 
by the retaining wall; the building of sewers and the laying 
of water and gas mains; the building of trestles to support 
street traffic; and the construction of the two twin tunnels 
under Ninth Avenue. 

These contracts demanded that the material excavated be 
delivered on board scows to be furnished by the railroad com- 
pany, alongside the pier at the foot of West Thirty-second Street, 
North River. These scows were supplied, and the material 
was disposed of from the pier, by Henry Steers, Incorporated, 
under a contract which called for the transportation and placing 
of all material so delivered in the Pennsylvania Railroad Com- 
pany's freight terminal at Greenville, N. J. 

The disposal of the excavated material was one of the 
principal features of the work, and the above contract covered 
the disposition of material from those portions of the terminal 
site east of Seventh Avenue and west of Ninth Avenue, from all 
substructural work and from other construction. 

91 



92 



SUBWAYS AND TUNNELS OF NEW YORK 



The central power plant for conducting this section of the 
work consisted of the following items: 

Four Ingersoll-Rand straight line air compressors. 

One Ingersoll-Rand duplex Corliss steam driven compressor^ 
cross-compound, with a capacity of 5600 cubic feet per minute 
compressed to 80 pounds at 70 r.p.m. 

Three Ingersoll-Rand duplex electric-driven air compressors, 
driven by 525 h.p., 6600 volt General Electric motors, with a 




Ingersoll-Rand Rock Drills in P. R. R. Terminal Excavation. 

capacity of 3000 cubic feet per minute, compressed to 80 pounds 
at 125 r.p.m. 

Two 10- by 6- by 10-inch Worthington steam pumps. 

One 7 J h.p. General Electric motor, driving the coal conveyor. 

One 8- by 10-inch Buffalo Forge Co's engine driving the 
forced draft fan. 

Three 500 h.p. Stirling water tube boilers. 

In the repair shop attached to this work, were two large 
Ajax drill sharpeners which took care of the steels from the 
rock drills in the excavation. 



EXCAVATION FOR THE TERMINAL STATION 



93 



In the pit excavation equipment the following items were 
included : 

Three 70-ton Bucyrus steam shovels. 

Two 30- ton steam shovels (Marion and Ohio). 

Eighty Ingersoll-Rand rock drills. 

Two Ingersoll-Rand quarry bars. 

Twenty-one 10- by 16-inch, 36-inch gage Porter locomotives. 

Three 9- by 16-inch, 36-inch gage Davenport locomotives. 



f'a 

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EL326.34- 




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^rrS?i3| 4 n ^Subgrade 232.40 



N3ubgradeTSievr274.71 
SECTION 190+00 



South Abul meet— | NIN TH f! 8%AVENUE 

"fc! ?i8iyNoiti 

0> AbutED 

5 1 SKETCH PLAN 



TERMINAL STATION WEST 

TYPICAL SECTIONS 



Cross-Sections of P. R. R. Terminal Excavation. 

One hundred and forty four-yard Western dump cars. 

One hundred and sixty-five flat cars with four-yard iron skips. 

The machine equipment at the dock included six stiff-leg 
derricks with 35-foot masts and 40-foot booms operated by 
60 h.p. three-drum Lambert hoisting engines with Northern 
motors, and eight Dodge electric telphers with General Electric 
motors. 

Ground was broken under the principal contract July 9, 
1904. Two methods were used in making the excavation for the 
retaining walls and in building these walls; construction in the 
trench, and construction on the bench. In general, the trench 
method was used wherever the rock on which the wall was to be 



94 SUBWAYS AND TUNNELS OF NEW YORK 

built was twelve feet or more below the surface of the street or 
where the buildings adjoining the wall were not founded on rock. 

In the trench method the base of the wall was staked out 
on the ground surface and as much width was added as was 
needed for sheeting and working space. All of this was then 
excavated to a depth of 5 feet before timbering was begun. 
A cable-way was erected and the spoil placed in buckets and 
dumped into wagons. Some very difficult material was encoun- 
tered in the deeper excavations; beds of quicksand were passed 
through varying from 1 to 18 feet in thickness. 

After encountering a fine sand in one trench no headway 
was made until a tight wooden cylinder was sunk through the 
sand by excavating the material inside of it and heavily weighting 
the shell with pig iron. When this cylinder had reached the 
gravel which lay below the sand, it was used as a sump, and the 
water level kept below the excavation, which permitted good 
progress. Sand continued to flow under the sheeting to such 
an extent that the front walls of four adjoining buildings were 
badly cracked and had to be rebuilt. 

The bench method of excavation for the retaining wall was sim- 
ple, and was used only when the rock lay near the surface and when 
the adjoining buildings had a rock foundation. As the overlying 
material was dry and firm, little or no shoring was required. 

The concrete retaining walls were usually built in sections 
50 feet long. The trenches were not allowed to be opened for 
the full depth. Concreting was started as soon after the 
necessary length of rock had been uncovered as the forms and 
preliminary work for a section could be prepared. Generally 
each section was a monolith. The concrete was mixed by 
power in the proportions of 1 part of cement, 3 parts of sand, 
and 5 parts of stone. Facing mortar 2 inches thick was deposited 
at the same time as the concreting, being separated from the 
latter by a steel diaphragm until both were in place. The 
diaphragm was then removed and the two spaded together. 
The layers of concrete never exceeded 8 inches in thickness. 

After a section of the concrete wall had firmly set, both 
back and front forms were removed and the thrust from the 



EXCAVATION FOR THE TERMINAL STATION 



95 



-Elev.Top of Curb, 31etSt 



Eley.Top of Curb, 31st St. 



262.2'to Left Cen. Line Terminal M, 
26'M'to Right jX 



0--6 Gas 

O— -6"Gaa 

O— 12"watei 




C'Gas 



15 Sewer 



TYPICAL SECTIONS 

OF RETAINING WALL 

IN THIRTY-FIRST STREET 



Retaining Walls for P. R. R. Terminal Excavation. 



96 SUBWAYS AND TUNNELS OF NEW YORK 

sides of the trench transferred directly to the finished wall. 
The face of the wall was rubbed with a cement brick to remove 
the marks of the planks, and washed with a thin cement grout. 

Waterproofing and brick armor were then continued up the 
back of the wall, the waterproofing consisting of three layers of 
" Hydrex " felt and four layers of coal-tar pitch. The pitch con- 
tained not less than 25 per cent of carbon, softened at 60 degrees 
Fahrenheit and melted at between 96 and 106 degrees Fahrenheit. 

In designing the concrete wall the following were assumed: 

Weight of concrete, 140 pounds per cubic foot. 

Weight of material from the ground surface to the depth of 1 2 
feet, 100 pounds per cubic foot; and the angle of repose 30 degrees. 

The weight of buildings back of the wall was neglected, as 
it was assumed to be about equal to that of the cellars filled with 
material weighing 100 pounds per cubic foot. 

Reaction from superstructure, live and dead load, 20,000 
pounds per lineal foot of wall. 

Weight of materials below the 12 -foot depth line, 124 pounds 
per cubic foot. 

The resultant of both horizontal and vertical forces should, 
at all points, fall within the middle third of the wall; in other 
words, there should be no tension in the concrete. 

While the pit excavation was started by hand, three 70-ton 
steam shovels were put to work as soon as they could be delivered. 
The excavated material was loaded by the shovels into 2 -yard 
end-dump wagons and conveyed to the dumping board at 
Thirty-fifth Street. . 

The average number of teams employed was 140, 10 per 
cent of which were snatch teams to pull the wagons out of the 
pit, and to assist them up the runway at the dumping board. 
The teams averaged only seven trips per day of ten hours. 
The number of teams was not sufficient to keep the three shovels 
busy when in good digging; but the dumping board was taxed 
to the limit of its capacity. 

As the shovels had three-and-one-half-yard buckets, one 
bucketful meant a wagon full and running over. The output 
from August to November inclusive averaged 40,000 cubic 



EXCAVATION FOR THE TERMINAL STATION 97 

yards per month. One shift only was worked per day. The 
quantity was not large for such shovels to dig, but it was a large 
quantity to truck through the streets and required the passage, 
at a given point, of one team every 18 seconds. 

At the beginning of the team transportation period, on May 
22, 1905, two shifts of ten hours each were inaugurated, and 
the earth was handled at the rate of 85,000 to 90,000 cubic 
yards per month. But by the end of August, when a little 
more than 60 per cent of the total earth had been disposed of, 
the rock began to interfere with the progress. The strike of 
the rock was almost directly north and south, and its surface 
formed broken ridges in that direction with deep valleys between. 
The dip was almost vertical near Ninth Avenue and about 
70 degrees toward the west near Seventh Avenue. This made 
it necessary to turn the shovels parallel to the ridges in order 
to strip the rock for drilling. As the ridges were very much 
broken the shovels continued to bump into them on all occassions, 
making it necessary to move back and start other cuts, or 
stand and wait for the rock to be drilled and blasted. 

A small Vulcan steam shovel with a three-quarter-yard 
dipper was brought on the work to do the stripping. It was 
moved so readily from place to place that another shovel of 
smaller type was put in use and thereafter the stripping was 
done largely by these two small shovels and by hand. The large 
shovels were used almost exclusively in handling rock. 

The drilling necessary to remove the rock was very large 
in total amount and also in amount per yard excavated. In 
order not to damage the retaining walls and the rock underlying 
them, holes spaced at five-inch centers were drilled 1 foot away 
from the face of the holes and on the same batter. These 
breaking holes alone amounted to a total of 210,000 lineal feet 
or 1 foot of hole for each 3J cubic yard of rock excavated. The 
regulations of the Bureau of Combustibles which prohibit 
springing of holes compelled the placing of drilled holes very 
close together, making a total of about 420,000 lineal feet which, 
added to the other 210,000 lineal feet, brings the aggregate 
to 630,000 feet. If to this is added the block holes (for some 



98 SUBWAYS AND TUNNELS OF NEW YROK 

of the rock broke large) it will show at least i foot of hole drilled 
for each cubic yard of rock excavated. 

The excavated material was hauled from the shovels to the 
pier in io-car trains. The cars were of three classes, namely, 
4-yard dump cars, flat cars and flat cars carrying 4-yard 
skips. So far as practicable, earth and rocks of one cubic 
yard or less were loaded in the dump cars; larger rocks on the 
flat cars; and medium sized rocks in the skips. The dump 
cars were run at once to the hoppers, dumped and returned 
to the pit; the flat cars and skips were run under the derricks 
and telphers and the large rocks unloaded, after which they 
were run to the hoppers and emptied. 

The total quantity of excavated material handled on this 
pier from May 22, 1905 to December 31, 1908 amounted to 
673,800 cubic yards of earth and 1,488,000 cubic yards of rock, 
place measurement. This is equal to 3,208,400, cubic yards, 
scow measurement. In addition to this, 175,000 cubic yards 
of crushed stone and sand, and 6000 car loads of miscellaneous 
building materials were transferred from scows and lighters 
to smaller cars for delivery to the Terminal work. 

All the earth and 570,000 cubic yards of rock, place measure- 
ment, were handled from the chutes. The remainder of the rock, 
amounting to 918,000 cubic yards, and all the incoming material 
were handled by the derricks and telphers. In materials- 
handling capacity one telpher was about equivalent to one 
derrick. A train, therefore, could be emptied or a boat loaded 
under the bank of eight telphers in one-quarter of the time 
required by the derricks, of which two only could work on one 
boat. The telphers were of great advantage where track room 
and scow berths were limited. 

The material from various contracts of the Pennsylvania 
Railroad extension, which was transported and disposed of 
by Henry Steers, Incorporated, amounted to 4,457,800 cubic 
yards. Of this, 3,454,800 cubic yards were placed in the freight 
terminal yard at Greenville, N. J.; 711,900 cubic yards in the 
Meadows division; and 291,000 cubic yards at other points. 
Handling this material required the loading of from ten to twenty 



EXCAVATION FOR THE TERMINAL STATION 



99 



scows per day. The average for more than two years was 
fourteen per day. As the average time spent in one round trip 
was three and one-third days, a fleet of more than fifty scows 
was required to keep all points supplied. All loaded scows 
were towed from the docks to stake boats about one mile 




Drilling for P. R. R. Terminal Excavation. 

off shore at Greenville. From there they were taken to the 
different unloading points by smaller tugs which also returned 
the empty scows to the stake. 

The unloading plants were similar at the different points, 
although that at Greenville was much larger than the others. 
It included five land dredges and eight traveling derricks of two 



100 SUBWAYS AND TUNNELS OF NEW YOKK 

types, one floating and the other mounted on wheels and traveling 
on a track of 16-ft gage. The derricks, which were of the 
" A " frame type and capable of handling 20 tons, were used 
for the larger rocks which were deposited by the derricks either 
in the channels along which they worked or in the fill along 
shore, without the use of cars. The land dredges had 60-foot 
booms, carrying two-and-one-half-yard Hayward buckets 
operated by a 14- by 18-inch double-drum dredging engine. They 
loaded into 9-yard, standard gage, side dump cars, built by 
the contractor; and unloaded the scows to within one foot 
of the deck. The material remaining was loaded by hand into 
skips which were dumped into the cars by small derricks, one 
of which was located at the rear of each dredge. The cars were 
hauled to the dump by 2 5 -ton standard gage locomotives. 

The cost of repairs to the scows, due to loading, transporta- 
tion and unloading at all points, was about three and one-half 
cents per cubic yard. In addition it cost four-tenths of a cent 
per cubic yard for scows overturned or sunk in service, making 
three and nine-tenths cents in all. 

The two double-track tunnels under Ninth Avenue, which were 
constructed to obtain 100 feet of additional tail room on each of 
the four tracks, required an excavation 75 feet wide. The rock 
was of fair quality, but not firm enough to support so great a span 
in a single tunnel. To obviate the necessity of timbering, the 
center wall was built before excavating for the full width. The 
dip of the rock at this point is almost 90 degrees. To prevent 
blowing away the entire face in excavating for the tunnel, the pit 
excavation was not carried west to the final face below the 
springing line, but a 10-foot bench was left at that elevation. 

A top heading 9 by 9 feet in section was started above the 
bench, and when 10 feet had been penetrated it was widened 
to 20 feet. A cross-heading was driven in each direction at the 
west end of the first heading. The bench was then shut down 
and the first 10 feet of longitudinal heading was widened suf- 
ficiently to receive the center wall. 

When the middle wall had been concreted all voids between 
the top and the rock were grouted through pipes left for the 



EXCAVATION FOR THE TERMINAL STATION 



101 



purpose. The wall was then protected by curtains of heavy 
round timber securely wired together and the remainder of the 
excavation was made by widening the cross-headings toward 
the face. The muck was carried out by cableways, one on each 
side of the completed wall. Each cableway was supported by 
a tower outside the tunnel and by a large hook-bolt grouted 
into the rock at the inner end of the tunnel. Forms were built 
for each tunnel complete, and the concrete was delivered by a 




Looking east at Seventh Avenue. Approach to new Pennsylvania Terminal, 
with Cameron Pump removing 400 gallons drainage water per minute 
from the diggings to the sewer 65 feet above. 

belt conveyor, running over the top of the lagging and moved 
out as the tunnel was keyed.* 

The rock formation consisted of quartz, feldspar and mica, 
with some hornblende, serpentine, pyrites and tourmaline. 
The formation varied from mica schist to granite and may be 
generally classed as gneiss. The total rock excavation with an 

*From a paper by George C. Clark, M.A.S.C.E., on The New York Tunnel 
Extension of the Pennsylvania Railroad and The Site of the Terminal Station, 
in the Proceedings of the A.S.C. E., March, iqio. 



102 



SUBWAYS AND TUNNELS OF NEW YORK 






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EXCAVATION FOR THE TERMINAL STATION 103 

average depth of 50 feet was about 450,000 cubic yards in 
open cut. The general method of drilling for the different 
classes of work was as follows : 

In breaking down, the holes were started about 8 feet apart, 
on a slight batter, so that at the bottom they would be less 
than 8 feet apart. They were drilled 10 feet deep, and it was 
necessary to load heavily to lift the cut. When a side cut 
of about 20 feet had been made, the side holes were drilled 20 
feet deep and the holes loaded and tamped for the full 20-foot 
cut. The terms of the specifications required the contractor 
to finish the sides of the excavation by broaching holes. 

For the steam shovel excavation, on portions of the work 
spring holes were used. These holes were 20 feet deep. Two 
or three sticks of dynamite were exploded at the bottom of the 
holes, and no tamping was used. This process was repeated 
with increasingly heavy charges until a cavity was formed of a 
size which would hold from 100 to 200 pounds of dynamite. 
Face and breast holes were drilled, and by this means cuts 20 
feet by 15 feet thick were broken up. 

The average performance from more than 25,000 drill shifts 
showed 33 lineal feet of hole per 8-hour shift. The average 
cubic yards per drill shift was 13.9. The average drilling per 
cubic yard was 2.4 feet. The dynamite used was 60 per cent, 
and the average excavation per pound of dynamite was 2.2 
cubic yards. The average performance of derricks, with gangs 
of twelve men and one foreman, was 50 cubic yards per 8-hour 
shift. The cost of field engineering and office was 2.8 per cent of 
the cost of work executed, of which 2.7 per cent was for salaries. 

The quantities of some of the main items in the excavation 
of the Terminal Station are as follows: 

Excavation, in cubic yards 517 ,000 

Cement used (concrete and grout), barrels 33,000 

Concrete, cubic yards 18,500 

Dynamite for blasting, pounds 206,000 

Structural Steel (including Pier 72), pounds 1,475,000 

*From a paper by B. F. Cresson, Jr., before the A.S.C.E., April 6, 1010. 



CHAPTER XIII 

CROSS-TOWN TUNNELS OF THE PENNSYLVANIA RAILROAD 

On May 29, 1905, a contract was entered into with the 
United Engineering and Contracting Company for the construc- 
tion of the tunnels for the Pennsylvania Railroad extending 
eastward from the easterly extension of the Terminal Station 
in New York City to the permanent shafts just east of First 
Avenue, where they connected with the East River tunnels. 

These cross-town tunnels are located under Thirty-second 
and Thirty- third streets, from the Terminal Station to Second 
Avenue. Curving thence to the left, they pass under private 
property and under First Avenue to the shafts. 

The method of handling the work adopted by the contractor 
was in general as follows: Excavation was carried on by 
modifications of the top-heading and bench method, the bench 
being carried as close to the face as possible in order to allow 
the muck from the heading to be thrown by the blast over the 
bench into the full tunnel section. The spoil was loaded into 
3 -yard buckets of a special design by means of Marion steam 
shovels operated by compressed air; and these buckets were 
hauled to the shafts by General Electric electric locomotives. 

Electrically operated telphers suspended from a timber 
trestle hoisted the buckets and, traveling on a mono-rail track, 
deposited them on wagons for transportation to the dock. 
At the dock the buckets were lifted by electrically operated 
stiff-leg derricks and the contents deposited on scows for final 
disposal. The spoil was thus transported from the heading to 
the scow without breaking the bulk. When the concreting 
was in progress the spoil buckets were returned to the shafts 
loaded with stone and sand. 

104 



A 








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m 

o 

=$ 

-5*10f 

= 1 gl 
.©a, 



' & Tel. 
pduits 



£■!— 2*'^ 




SHIELD CHAMBERS ARCH TIMBERING 




JUNCTION OFSHIELD CHAMBERS WITH RIVER TUNNELS 



V I 



ai^i 



IT V-4 




JUNCTION 19'6"AND 24'6"SPANS 







m t- 



E=^= 




TYPICAL SECTIONS. 

THIRTY-SECOND STREET TUNNELS 

SHIELD CHAMBERS, ETC. 



h-^H* 



'.i V. ti'iin Twin Tunnels, 



1 > 



.-<-™sr 



m ,i 1 1 



19'0"SPAN TWIN TUNNELS, ELLIPTICAL ARCHES 

Typical Cross-Sections, Pennsylvania R.R. Cross-Town Tunnels. 




I Siuui Twin Timuels, Open Cut 



CROSS-TOWN TUNNELS 105 

The power house at the corner of Thirty-first Street and 
Fourth Avenue supplied compressed air for operating the 
drills, shovels, pumps and hoists in the tunnel driven from the 
river shafts. It included three Laidlaw-Dunn-Gordon com- 
pressors. The largest was a 2-stage, cross-compound, direct- 
connected, electric unit, 32 and 20 by 30 inches, driven at 100 
r.p.m. by a 480 h.p., 230-volt, direct current Fort Wayne 
constant speed motor. This unit was rated at 2870 cubic 
feet of free air per minute at a pressure of 100 pounds. It was 
governed by throttling the suction, the governor being con- 
trolled by the pressure in the air receiver and the motor running 
continuously at regular speed. The two other compressors 
were of smaller type; one 22-I and 14 by 18 inches, rated at 
1250 cubic feet of free air per minute at 100 pounds pressure; 
the other 16 and 10 by 18 inches, rated at 630 cubic feet per 
minute. They were driven at 150 r.p.m. by 105 h.p., 220- 
volt, direct current General Electric motors, having a speed of 
655 r.p.m. The larger of these two compressors was driven 
by two of the motors belted in tandem, and the smaller was 
belt-connected to a third motor. All of these compressors 
were water-jacketed and fitted with intercoolers, the water 
supply for cooling purposes being furnished by a water cooling 
tower. 

The Dodge telphers used for hoisting muck from the tunnels 
and for lowering supplies, were hung from single rails on a 
timber trestle about 40 feet high spanning and connecting 
the two shafts. They were operated by a 75-h.p. General 
Electric motor for hoisting, and a 15-h.p. Northern motor 
for propelling. Their rated lifting capacity was 10,000 pounds, 
at a speed of 200 feet per minute. 

During excavation the headings were supplied with forced 
ventilation from 12- and 14-inch Root spiral riveted asphalted 
pressure pipes. Canvas extensions were used beyond the ends 
of the pipes and air was supplied by a blower driven by a 
15-h.p. motor. 

The air compressing plant for the intermediate shaft was 
located at the rear of the Thirty-third Street shaft and supplied 



106 SUBWAYS AND TUNNELS OF NEW YOEK 

air for driving the tunnels east and west from the shafts, both 
under Thirty-second and Thirty-third Streets. Two Laidlaw- 
Dunn- Gordon compressors, similar to the larger machine in 
the First Avenue plant, were here installed, with a similar 
water cooling tower. The equipment also included American 
blowers with General Electric motors for forced ventilation. 

For the receipt and disposal of materials at the Thirty- 
fifth Street pier, there was an equipment of four stiff-leg der- 
ricks operated by Lidgerwood and Lambert electric hoists. 
Two were used in lifting the muck buckets from the wagons 
and dumping them on the scows for final removal. The other 
two were fitted with clam-shell buckets for unloading sand and 
broken stone from the barges and for depositing the materials 
in large hoppers from which they were drawn into wagons for 
transportation to the various concrete plants. 

In the tunnels the loading was done with air operated steam 
shovels. Four of these, Marion Model 20, were used at various 
points of the work. The material was carried from the shafts 
in buckets of special design. The buckets were carried in 
the tunnel on flat cars and through the streets on wagons, 
both cars and wagons being provided with cradles shaped 
to receive them. The tunnel cars were hauled by standard 
10- ton General Electric electric mine locomotives, the current 
for which was taken at 220 volts from a pair of trolley wires 
suspended from the roof of the tunnel. Two eight-and-one- 
half-ton Davenport steam locomotives were also used toward 
the end of the work. The steam shovels were supplemented 
by two 15-ton Browning locomotive cranes which handled the 
spoil in places where the timbering interfered with the 
operation of the shovels. All tracks were of 3-foot gage and 
laid with 40-pound rail. 

Practically all of the heavy drilling was done with Ingersoll- 
Rand " E-52 " rock drills, the trimming being done with 
" Little Jap " and " Baby " drills. A large number of pumps 
were used at various points of the work, practically all of them 
being of Cameron make. The grout machines were of the 
vertical cylinder, air stirring type. 



CROSS-TOWN TUNNELS 107 

The sinking of the intermediate shafts was the first work 
undertaken. The shaft at Thirty-third Street had a cross- 
section of 34+ feet by 21 feet, and was 83 feet deep. The 
rock surface averaged 5 feet below the ground surface. Sinking 
was started on July 10, 1905, and was completed on October 3d 
of the same year, the rock throughout being hard and dry. 
The average daily rate of sinking was 0.73 feet and an average 
of 1 7. 1 cubic yards was excavated per day with two shifts of 
eight hours each. The first shift was started at 6 a.m., and the 
second at 2 :3c p.m., ending at n p.m. These hours were adopted 
to avoid undue disturbances during the night. 

Before blasting the first lift of rock, channel cuts 5 or 6 feet 
deep were made along the sides of the shaft in order to avoid 
damage to the walls of the neighboring buildings. Timber- 
ing was required for a depth of only 10 feet below the surface 
of the ground. A drift 30 feet long, 17 feet wide and 27 feet 
high connected the south end of the shaft with the tunnels. 
This drift was excavated in three stages, a top heading and 
a bench in two lifts. While blasting the cut in the top heading, 
concussion was sufficient to break glass in the neighboring 
buildings. The use of a " Radialaxe " machine for making 
a cut to blast on open ends reduced this concussion. 

The construction of the Thirty-second Street shaft was 
similar to that at Thirty- third Street, this shaft being 31^ by 
20J feet in section, with a depth of 71 feet. The depth of 
earth excavation averaged 19^ feet. Sinking was started 
May 15, 1905, and completed on the 26th of the following 
October. The daily average rate was 0.3 feet in earth and 0.52 
feet in rock. The drift from shaft to tunnel was excavated 
in much the same manner as the one at Thirty-third Street. 

For an average distance of 350 feet from the First Avenue 
shafts there were four single-track tunnels. The rock was 
sound and dry. A top heading of the full size of the tunnel 
and about 8 feet high was first driven, drilling being done by 
four drills mounted on two columns and the holes blasted in 
the ordinary way. The bench was 13 feet high. Drills on 
tripods were used on the bench, but owing to the lack of head- 



108 SUBWAYS AND TUNNELS OF NEW YORK 

room, steels long enough to reach the bottom of the bench 
could not be used. Drills on tripods were placed as low as 
possible and lift holes were drilled 1 5 degrees from the horizontal 
at the bottom of the bench. Headings were driven 10 to 20 
feet in advance of the bench. In these single tunnels the muck 
was loaded by hand. 

From the end of the single-track tunnel westward to Fifth 
Avenue on Thirty- third Street and to Madison Avenue on 
Thirty-second Street (with some exceptions) each pair of tunnels 
was excavated for the entire width at one operation. Three 
distinct methods were extensively used. The double heading, 
the center heading and the full-sized heading method. These 
differed only in the manner of blasting and drilling. The 
bench was usually within 10 or 15 feet of the face and was 
drilled and fired in the same way as in the single tunnels. 

In the double heading method the top headings for each 
tunnel were driven separately, leaving a short rock core wall 
between them. These headings were drilled from columns 
in the same manner as in the single tunnels. The temporary 
dividing rock wall between the headings was drilled by a tripod 
drill on the bench of one of the headings, and was fired with 
the bench. 

In the center heading method only one heading was driven, 
rectangular in shape and about 8 feet high by 14 feet wide. 
It was on the center line between the tunnels. In general, 
the face was from 6 to 12 feet (the length of one or two rounds) 
in advance of the face at the top. The center heading was 
drilled by four drills mounted on two columns. By turning 
these drills to the side they were used for holes at right angles 
to the line of the tunnel; and by means of these latter holes 
the remainder of the face of the heading was blasted. By 
turning the drills downward the bench holes under the center 
heading were also drilled. 

Where the full heading method was employed ten drills 
were mounted on five columns across the face. Holes were 
drilled to form a cut near the center line between the tunnels. 
The remainder of the holes were located so that they would 



DING 



fe> 




Methods of Excavation, Pennsylvania R.K. Cross-Town Tunnel: 




1MJ 



VJi 



./Neat line 



SECTION SHOWING NORTH AND SOUTH HEADING, ALSO ENLARGEMENT 
TO SINGLE HEADING AND METHOD OF TIMBERING 




IETHOD 01 



Standard Section Line 
Neat Line 



CARRIAGE FORN 
CROSS-TOWN 




CROSS-SECTION 



Methods of Excavation and Timbering 




EXCAVATION AND TIMBERING 

IN 

HEAVY GROUND 

OF 



THREE-TRACK TUNNEL OF 33D ST. 



TING BENCH, SHOWING CENTER EXCAVATION 

WITH TIMBERING ALSO 
VIENT TO FULL SIZE AND TIMBERING 



SIDE WALLS 
TUNNELS 

^o'o^ 



-ftyf- 





Description 


Piece 


Location 


Size 


l 


Studs 


4"x8" 


2 


Diagonals 


i'x6'x:i' 


3 


Lagging 


2"dressed 15 'lg 


4 


Braces (oak) 


2"x 8"x3' 


5 


Jacking Timbers 


Ox 6" 


G 


Knee Braces 


2x 10x6 '6" 


7 


Floor Joists 


3"x 12x1* 'e" 


8 


Flooring 


2'x 10" 


9 


Diagonal Braces 


3"x 6 ' 


10 


Posts 


3"xl2''' 


11 


"Wedges 




12 


Braces (pine) 




\i 


Tie Rods 


r tr"x T'o" 


14 


Top Chord 




15 


Bottom Chord 






-30 



3ITUDINAL SECTION ON C. L. OF CARRIAGE 

ylvania R.R. Cross-Town Tunnels. 



CROSS-TOWN TUNNELS 



109 





Construction of twin tunnels through excavation started for three-track 
tunnel in Thirty-third Street near Fifth Avenue. 



110 SUBWAYS AND TUNNELS OF NEW YORK 

draw into the center of the cut. The bench was frequently 
drilled from the same set-up of columns by turning the drills 
downward. In sound rock this method proved to be the most 
rapid of the three. 

Practically all trimming was left until immediately before 
the concreting was begun. It was then taken up as a separate 
operation, but proved to be costly and tedious, and a hindrance 
to the placing of the lining. The rock encountered was Hudson 
schist, varying widely in character. 

The material excavated from the tunnels was dumped on 
barges at the Thirty-fifth Street pier. These barges were 
towed to points near the Bayonne Peninsula where the spoil 
was used principally in the construction of the Greenville freight 
terminal. A portion was also used in building the extension 
across the Hackensack meadows to the Bergen Hill tunnel. 
The average rate of advance in the full-sized tunnels was from 
3.8 to 4.7. feet per day, in the full-sized twin tunnels, from 

1.4 to 5.8. feet per day, and in exploration drifts from 4.6 to 

6.5 feet per day. 

From a paper by James H. Brace and Francis Mason, in the Proceedings of 
the A.S.CE. for October, 1909. 



CHAPTER XIV 

THE EAST RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

From the inception of the Pennsylvania Railroad project 
it was recognized that the most difficult and expensive section 
of the work would be the tunnels under the East River from 
Manhattan Island to Long Island. The borings along the 
line of the tunnel in the river bed had shown a great variety 
of materials to be passed through, comprising quicksand, 
coarse sand, gravel, boulders and bed rock, as well as some 
clayey materials. The rock was usually covered by a few feet 
of sand, gravel and boulders intermixed; but in places where 
the rock surface was at some distance below the tunnel grade, 
the material to be met was quicksand. The nearest parallel 
in work previously done was found in some of the tunnels under 
the Thames River, England, and particularly in the Blackwell 
tunnel, where open gravel was passed through. 

The contract covering this section of the work was entered 
into with S. Pearson & Son on July 7, 1904. This contract 
covered the permanent shafts in New York City and in Long 
Island City, the tunnels between these shafts, and their 
extension eastward in Long Island City to East Avenue, involv- 
ing about 23,600 feet of single-track tunnel. The contract had 
many novel features and seemed to be peculiarly suitable, con- 
sidering the unknown risks involved and the unusual magnitude 
of the work. 

A fixed amount was named as the contractor's profit. If 
the actual cost of the work when completed, including the sum 
named as contractor's profit, should be less than a certain 
estimated sum named in the contract, the contractor should 
have one-half of the saving. If on the other hand the actual 
cost of the completed work, including the fixed sum for con- 
ill 



112 SUBWAYS AND TUNNELS OF NEW YORK 

tractor's profit, should exceed the estimated cost named in the 
contract, the contractor should pay one-half the excess and 
the railroad company the other half. The contractor's liability, 
however, was limited to the amount named for a profit plus 
$1,000,000. In other words, his maximum money loss would 
be $1,000,000.* 

The plant assembled by S. Pearson & Son for handling this 
section is believed to be the most extensive ever placed on a 
single piece of contract work. The minimum plant to be pro- 
vided by the contractors for the undertaking was specified by 
the railroad company in' part as follows: The tunnels were to 
be driven eastward from shafts in Manhattan Island and west- 
ward from the temporary shaft to be built near East Avenue 
in Long Island City, making a total of eight headings, in all 
of which work was to be prosecuted simultaneously with the 
utmost practicable diligence. The contractor was to provide 
on each side of the river an adequate plant which was to include 
boilers, air compressors, hydraulic machinery, dynamos and 
all other necessary equipment, with a reasonable duplication 
to meet unusual and unexpected emergencies. 

The air compressors were to be of sufficient capacity to 
deliver regularly into each heading at least 300,000 cubic feet 
of free air per hour at a pressure of 50 pounds per square inch 
above the normal air pressure; and for a larger amount if found 
necessary during the progress of the work. The air for the 
compressors was to be drawn from the exterior of the power 
house and the intake was to be so located as to give pure air. 
This air was to be cooled and freed as completely as possible 
from oil and other impurities before delivering into the heading. 

In order to provide a reasonable margin for repairs and 
contingencies, a spare compressor and boiler plant was to be 
provided on each side of the East River, and to be kept in good 
condition, ready for immediate use. The capacity of these 
spare plants was to be 25 per cent of that required in the 
preceding paragraph for regular operation. 

* From paper by Alfred Noble, Past President Am. Soc. C.E. in the Proceed- 
ings of the A.S. of C.E. for September, 1909. 



Rock — ' 



--.= =T^:j- 



Vaterproofiiy -j 





ITH CONCRETE-DIVIDING WALL 



■y.y'^y 



Steel Bars 




y;^y 

m 



:y-: 

Elev. of Top of Rail Y feg^s PSP - 




'■'riii5 c 



■V.-Vi-.v-: 

;:.•"■■•.-;; ... _ j ?- 









rifled Drain Pipe 






CROSS PASSA( 



Typical Tunl 




SPLICING CHAMBER 

FOR HIGH TENSION CABLES 



i Elev. of Top of Kail 



Jfe 



REFUGE NICHE 





TWIN TUNNEL WITH CONCRETE-DIVIDING WALL 







«>:?'•• 










•i 




. 






i 




,-* Uni 






M 


if 


1 







TWIN TUNNEL WITH ROCK-DIVIDING WALL 







SPLICING CHAMBER 



"1,3 



Typical Tunnel Sections, Pennsylvania U.K. in Nen Y( 



BOROUGH OF MANHATTAN 
.CITY OF NEW YORK 



PLAN AND PROFILE 
EAST RIVER TUNNELS 





BOROUGH OF MANHATTAN 
CITY OF NEW YORK 



BOROUGH OF QUEENS 
CITY OF NEW YORK 




PROFILE OF LINE A 



THE EAST RIVER TUNNELS 113 

Effective means were to be used to secure proper ventila- 
tion. The amount of carbonic acid at any working face or in 
any chamber must never exceed one part in one thousand parts 
of air. Suitable devices were to be used to deaden as much 
as practicable the noise of the air introduced and exhausted. 
When blasting was to be resorted to, special means were to be 
provided for the rapid removal of the fumes produced. 

Bulkheads were to be built in each tunnel at intervals of 
not more than iooo feet; and it was specified that there should 
at no time be an interval of more than iooo feet between 
a shield and the nearest bulkhead. These bulkheads were to 
be of concrete or brick set in Portland cement mortar, or of 
other construction to be approved by the company's engineer. 
Each was to be provided with two air locks near the bottom, 
at least 6 feet in diameter and 20 feet in length, for the passage 
of men and materials; one near the roof as an emergency lock 
for the passage of men only; and a pipe 12 inches in diameter 
and 30 feet long with a gate valve at each end, for passing 
pipes and rails. The emergency lock was to be of dimensions 
sufficiently ample to contain the entire force employed at any 
one time in the heading. 

Stairways and galleries were always to be maintained to 
give sufficient access to the locks. All parts of the bulkheads 
and air locks were specified to be of sufficient strength to sus- 
tain safely a pressure of 55 pounds per square inch. The 
pipes necessary for air supply, ventilation, hydraulic and elec- 
tric transmission, and other purposes were to be built into the 
bulkhead and provided with suitable connections. All of these 
pipes were to be standard lap welded. When a shield had been 
driven 500 feet or more from the shaft it was specified that at 
least two bulkheads should always be in use if compressed air 
was being used. 

A safety screen extending from the roof downward into 
the tunnel, of a design to be approved by the company's engineer, 
was to be maintained within 100 feet of each working face. 
Others were to be built at intermediate points between the 
working face and the nearest bulkhead, if necessary, to main- 



114 SUBWAYS AND TUNNELS OF NEW YORK 

tain a chamber filled with compressed air along the tunnel 
roof which would give access to the emergency lock. The 
galleries were to extend from the safety screen nearest the work- 
ing force to the first bulkhead. 

The shields were to be of ample strength and of the best 
materials ; were to be provided with hydraulic rams of sufficient 
power to move them along the alignment laid down on the plans 
and profiles; and they were to have adequate arrangements 
for the rapid execution of the work and for the safety of the men 
employed. 

These outline specifications were of help to the contractors 
in making their bids and deciding what plant should be installed. 
The plant put in by S. Pearson & Son fulfilled these requirements, 
but it was found that the porous materials overlying the tunnels 
increased the demand for air beyond that specified, and it 
became necessary to increase the plant. 

In the effort to select the best air compressors for continuous 
day-and-night service under the peculiarly difficult conditions 
of this work, the contractor made a careful investigation of 
plants erected by various manufacturers wherever available. 
Indicator cards of the steam and air cylinders were taken by 
the contractor's engineers where the plants were within reasonable 
distance; and where the plants were located too far away, 
indicator cards were submitted for inspection. 

After an exhaustive study of all the machines proposed and 
of their relative merits, it was decided to adopt the type of 
Ingersoll-Rand air compressor fitted with the latter company's 
air-thrown inlet and discharge valves, on account of the larger 
valve areas, the free openings for inlet and discharge, and the re- 
duced clearance spaces. This compressor was chosen in preference 
to other types with poppet discharge valves, as a high piston 
speed was necessary on account of the limited area at the dis- 
posal of the contractor for the installation of his plant. The 
choice of this type was amply justified as, during the four years' 
operation of the plant, it was never necessary to replace any 
of the forged steel, oil treated valves. 

There were four cross-compound steam duplex air low pres- 



T 



5-500 H.P. Boilers 




Combination HJ& L, Pressure High PressiiLS Compressor 
Compressor t t 



iL.P. 



Length o: 



Plan of the Manhattan Air Compressor Plant for Pennsylvania R.R. East River Tu 




CD 

c 
2 

a 
pq 

o 

XI 

+3 



? 150 ft. 



Fhis was the Largest, Most Complete Air Power Plant ever used for Contract Work. 



THE EAST RIVER TUNNELS 



115 



sure units, with steam cylinders 16 and 34 inches in diameter, 
air cylinders 26i inches in diameter, and a stroke of 42 inches. 
They compressed to 50 pounds pressure, with an aggregate 
free air capacity of 14,744 cubic feet per minute. A fifth machine 
was of the same type, same stroke and with steam cylinders of 
the same size, as the four previous units; but it had 152-inch 
duplex air cylinders designed to compress to 140 pounds. The 
in take of this latter compressor could be at atmosphere, or 




Interior of Manhattan Air Compressor Plant, P. R. R. East River Tunnels. 

at the discharge pressure of the four low pressure units, the 
latter increasing its delivery at high pressure about four times. 
The piston displacement of this machine was 13 10 cubic feet 
per minute at normal speed. 

The steam ends of these air compressors were of cross- 
compound Corliss type with trip release gear controlled by the 
governor on each cylinder. The steam cylinders and inter- 
mediate receiver were steam jacketed and a steam separator 
was mounted on the throttle valve. Steam was admitted at 



116 SUBWAYS AND TUNNELS OF NEW YORK 

a boiler pressure of 150 pounds (Stirling boilers) and the exhaust 
carried to Wheeler condensers at about a 26-inch vacuum. 
A test made to determine the steam consumption gave 14.2 
pounds of steam per i.h.p. hour when compressing up to 30 
pounds per square inch. An efficiency test of the low pressure 
compressor units on the Manhattan side showed a mechanical 
efficiency of over 90 per cent and a volumetric efficiency of 
about 96 per cent. 

In order to cover the demand of the specifications for a spare 
plant of 25 per cent capacity, a combination machine was 
designed which could be used either as a high pressure machine 
for rock drills or as a low pressure machine for supplying tunnel 
air. It had the same steam end as the low pressure units, but 
was fitted with two low pressure cylinders of 22j-inch diameter 
and two high pressure cylinders of 15^-inch diameter. Running 
as a low pressure machine with all four air cylinders operating, 
it had a capacity of 5,000 cubic feet of free air per minute. If 
it was desired to run it as a high pressure machine, the two low 
pressure cylinders could be disconnected, when the capacity 
was 1568 cubic feet of free air to 90 pounds pressure with atmos- 
pheric intake, and 6900 cubic feet of free air to 140 pounds pres- 
sure with an intake of 50 pounds from the low pressure units. 
Each air compressor was fitted with a vertical low pressure 
aftercooler, 57 inches in diameter and 14^ feet long, having 
920 square feet of cooling surface. These aftercoolers were 
fitted with tinned navy-mixture brass tubes and Tobin bronze 
tube plates. The air from each compressor was discharged 
into individual low pressure air receivers, 4J feet in diameter 
and 12 feet high. 

In addition to the steam driven low pressure machines 
it became necessary on the Long Island City side to purchase 
two low pressure Laidlaw-Dunn-Gordon electrically driven 
compressors. Each of these had two air cylinders, 30 inches 
in diameter by 4 2 -inch stroke, with rotative inlet valves. They 
were designed for a speed of 75 r.p.m. with a rope driven 
fly-wheel 20 feet in diameter weighing 20 tons and carrying 
fourteen 2-inch ropes. Horizontal aftercoolers of 1000 square 



THE EAST RIVER TUNNELS 



117 




o 
o 

5 



c3 



o 



,£3 



'■+3 
a> 



118 SUBWAYS AND TUNNELS OF NEW YORK 

feet of cooling surface each were attached, and the air was 
discharged into receivers 4? by 12 feet. These units were driven 
by Westinghouse 600 h.p., 440 volt, three-phase, 25-cycle 
motors running at 300 r.p.m. with a rope sheave 5 feet 2 inches 
in diameter. The motors took their current from three trans- 
formers of 375 kw. each, oil insulated and water cooled, receiv- 
ing current at 11,000 volts and transforming it down to 440 
volts. 

The great disadvantage of these electrically driven air 
compressors was that there was no way to regulate the volume 
of air discharged, as the speed of the motor could not be changed. 
The usual method of operating them was to open out on two or 
more tunnels requiring more than their combined capacity, and 
to adjust the volume of air by means of one of the steam 
driven units. 

As stand-by high pressure machines for the Manhattan 
side when the combination machines were on low pressure duty, 
two Ingersoll-Rand duplex, simple steam, 2-stage air com- 
pressors were installed with steam cylinders 16 inches in diameter 
and air cylinders 25} and i6J inches in diameter. The stroke 
of these units was 16 inches and each had a capacity of 1205 
cubic feet of free air per minute. 

y On the Long Island City side where little rock was encountered 
an Ingersoll-Rand " Imperial " compressor was installed as a 
stand-by while the combination machine was used on low 
pressure duty. This was a duplex, simple steam, 2-stage air 
compressor, with 16-inch steam cylinders, 15- and 25-inch air 
cylinders and 20-inch stroke. Its capacity was 1070 cubic 
feet of free air per minute at 100 pounds pressure. 

For starting up the headings at the East Avenue side at 
Long Island City, two Ingersoll-Rand straight line compressors 
were used, with steam cylinder 18 inches in diameter, air 
cylinder i8J inches and a 24-inch stroke. At 90 r.p.m. each 
had a capacity of 656 cubic feet of free air per minute compressed 
to 90 pounds. 

As there were ultimately two electrically driven air com- 
pressors on the Long Island side, and six low pressure units 



THE EAST RIVER TUNNELS 119 

and one combination unit on each side of the river; and as 
these machines were guaranteed to run at 125 r.p.m. con- 
tinuously for twenty-four hours, the maximum free air capacity 
of all the compressors, including the high pressure units, 
amounted to 102,922 cubic feet per minute. 

Steam at 150 pounds pressure was generated in twelve Stirling 
water tube boilers (six on each side of the river), each having 
a capacity of 500 h.p. with 10 square feet of heating surface 
per h.p. and 0.25 square foot of grate surface per h.p. The 
grates were 8 feet deep, and were of the McClave shaking type. 
Each boiler occupied a space 19 feet g\ inches by 18 feet 3 inches, 
and was about 21 feet high. Each had an independent steel 
stack 54 inches in diameter and 100 feet above grate level. 
The boilers were guaranteed to evaporate 8.7 pounds of water 
per pound of dry coal having a heat value of not less than 12,000 
B.t.u. and not more than 15 per cent of ash, from and at 212 
degrees Fahrenheit with a pressure in the ash pit of not less than 
2 inches and a draft at the damper box of 0.75 inch. This 
result was to be obtained with either No. 2 or 1 buckwheat 
anthracite; and in testing it was found that the boilers exceeded 
this efficiency. 

In computing the boiler capacity necessary, it was originally 
estimated, before finally deciding on the whole plant, that the 
i.h.p. requirements on each side of the river would be as 
follows: Electrical plant, 580; air compressors, 3325; hydraulic 
plant, 202; total, 4107 i.h.p. using 68,300 pounds of steam 
per hour. On the basis of eight pounds of water evaporated per 
pound of coal, this would represent 8500 pounds of coal per 
hour. Assuming four pounds of coal per boiler h.p., the 
capacity would be 2125 plus 531 (for the 25 per cent spare 
plant) or 2656 boiler h.p. This was taken to represent five 
boilers at 500 h.p. capacity. Ultimately it became necessary 
to increase the compressor plant and a sixth boiler was added 
on each side of the river. 

The boilers were arranged for forced draft. Two 6i-foot 
fans driven by 7-inch by 8-inch vertical engines were provided 
for each plant of five boilers. At East Avenue in Long 



120 



SUBWAYS AND TUNNELS OF NEW YORK 



Island City there were also four ioo h.p. locomotive boilers. 
These supplied steam to the two straight line compressors 
and also were used for driving fan engines for ventilation, the 
shaft pumps and steam derricks. 

With five boilers in operation the highest coal consumption 
on the Manhattan side for any one month was at the rate of 
800 tons per week. This is equivalent to 17 pounds per square 




Cameron Pumping Plant in Pennsylvania and Long Island R. R. Tunnel. 
The pump in the rear, nearest the air lock, is equipped with motor and 
electrically driven, while the pump in front is operated by compressed air. 

foot of grate surface per hour for five boilers. According to 
the records kept, the average consumption was 2.8 pounds of 
coal per i.h.p. per hour for all machinery. 

The coal used on the Long Island City side was No. 2 
buckwheat. On the Manhattan side where a greater 
demand was made on the plant, No. 1 buckwheat was 
used. The calorific value of the coal generally was from 
11,500 to 12,900 B.t.u., with ash varying from 13 to 20 per 
cent. As a result of a combination of poor coal and ineffi- 



THE EAST RIVER TUNNELS 



121 



cient firemen, the actual ash from the boiler varied from 20 
to 30 per cent.* 

For ordinary service work, the most suitable pump for 
}he rough work and large volumes of water proved to be the 
Cameron No. 12, with 18-inch steam and 12-inch water cylinders, 
and 20-inch stroke. At the East Avenue site of the works, a 
great number of pumps were necessary in the headings and break- 



■ 




\ H 1 


, 


* 


: 












L^i 


i "^Sa^i.-? 






M 


[v ■* 








'* W : 


S: 


#;• 




Vrlp 










' v? \ 




"' -*.. 


i' ^^; f a ( 


f 












9 ' 








- 













Photograph taken in Pennsylvania and Long Island R. R. Tunnel. Cameron 
Station Pump handling the drainage water, which seeps through the rock 
and earth that separate the tunnel from the river bottom. 

ups; and outside of the air-tight bulkheads at the lower end 
of this section, the No. 9 Cameron pump was generally adopted, 
although smaller sizes were used at various points. These 
pumps took up so little room that they stood at the side of the 
headings without interfering with the passage of cars. 

* From a paper by Henry Japp, M.A.S.C.E., on the " Contractor's Plant for 
the East River Tunnels " in the Proceedings of the Am. Soc. C.E. for Novem- 
ber, 1909. 



122 SUBWAYS AND TUNNELS OF NEW YORK 

Besides other qualities, the points of excellence peculiar 
to the Cameron design are simplicity, durability and the entire 
absence of outside valve gear or other moving parts. This 
pump has fewer working parts than any other pump; the steam 
mechanism consists of four stout pieces only, none of them 
delicate, intricate or exposed to injury. While under full pres- 
sure of steam the suction pipe may be lifted out of water and the 
pump allowed to run away or race as fast as steam will drive 
it, without danger of the piston striking the heads or any injury 
to the pump. Under most conditions as found on construction 
work, any pump is liable to have its supply of water cut off 
unexpectedly. With pumps of other design the sudden removal 
of the working load quite frequently results in the breaking of 
cylinder heads or other derangement that puts the machine out 
of service. The absence of outside gear of any kind permits 
the operation of this pump under adverse conditions or rough 
usage. Instances have occurred where this pump has started 
off and cleared a shaft of water when the pump itself had been 
buried for weeks under a mass of fallen rock and debris. 



CHAPTER XV 

THE EAST RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

{Continued) 

There were two types of shields used in carrying on this 
section of the work : The heavy type used in the tunnels under 
the river, and a lighter type used in driving the land tunnels 
from the East Avenue shaft, Long Island City, under the Long 
Island Station. The type used under the river was designed 
by Mr. E. W.Moir, Vice President of S. Pearson & Son, and was 
similar to that used in the Black well Tunnel, England, also 
designed by Mr. Moir. The principal feature distinguishing 
these shields from those used in the land section and from 
others used in subaqueous work around New York was their 
massive construction. The cutting edges were made very 
heavy, yet they proved none too heavy for the work before 
them. The cutting edge of one of them was turned up by 
being pushed on an almost imperceptible incline of rock and 
had to be repaired under air pressure. The total weight of 
each of these shields, without jackets or erectors, was 185 net 
tons. 

Eight subaqueous shields were used, 23 feet 6| inches in 
outside diameter, with horizontal floors projecting 9 inches 
in advance of the cutting edge between the vertical diaphragms 
and running back to the line of the cutting edge on each side. 
They were divided into nine pockets by two vertical diaphragms 
and two horizontal floors. The latter were made up of two plates 
f of an inch thick, and were non-continuous for a width of 6 
feet 10 inches, butting against the vertical diaphragms which 
were continuous for a width of 6 feet 10 inches. 

The outer shield was made up of three skin plates of f -inch 

123 



124 SUBWAYS AND TUNNELS OF NEW YORK 

steel, tHe outer and middle plates being 17 feet 6 inches long. 
The inner plate was 17 feet 3 inches long. 

The skin plates were divided up around the circumference 
in such a way that the shields could be built for transportation 
in eight sections, including the hydraulic jack boxes. The 
middle and inner skin plates lapped the outer plates by 1 2 inches 
and 24 inches respectively. 

In addition to the two vertical diaphragms there were two 
transverse bulkheads, 2 feet 6 inches apart, completely closing 
the shields except for openings made for doors and muck chutes. 
For each floor there was a pair of doors, one in each transverse 
bulkhead; and nine muck chutes pierced both bulkheads, 
with hinged doors on either end. A safety screen about 4 feet 
wide and 7 feet deep shrouded and surrounded the doors open- 
ing from the upper chamber. A drop safety curtain, 1 foot 6 
inches deep and f of an inch thick, was fixed along the roof 
of each chamber. The cutting edge was of cast steel, divided 
into segments machined on the radial joints and bolted together 
with turned and fitted bolts. 

The benefit of having the two transverse bulkheads was 
to give the shield an added stiffness which it required. The 
smallness of the doors and the muck chutes through these 
bulkheads handicapped for a while the mucking-out operations, 
especially in rock. After it was found that there was no likeli- 
hood of this feature being required, the transverse bulkhead in all 
three bottom pockets was cut out and the middle bottom pocket 
utilized for running the tunnel cars through the shield into the 
heading beyond on the tunnel track. 

To facilitate the passage of drill columns and timber to the 
upper pockets, part of the center pocket transverse bulkhead 
was also cut away. The 18-inch curtain suspended from the 
under side of each floor 18 inches in front of the bulkhead 
provided an air space for the men into which they could duck 
their heads if the shield was flooded. As the conditions obtain- 
ing under the East River had never been explored by a previous 
tunnel at the time this shield was started, many and varied 
contingencies were provided for in the accessories of the shield 




SECTIONAL ELEVATION 



(r) Ladder re 
diaphrag] 




FRONT ELEVATION 

East River Tunnel 



tfn. 



liaphragm omitted ■ 

it of control box 

te middle compartment! 



iiaphragm omitted • 
it of control box 
te middle corn-f- 
ed 
i) 




l'2M* 



SECTIONAL PLAN 




BACK ELEVATION 



'ennsylvania R.R. 



THE EAST RIVER TUNNELS 125 

which would not be necessary in future work under this river. 
The most satisfactory arrangement, in any type or mixture 
of types of materials found under the river was the bare shield, 
with the fixed hood projecting 3 feet in advance of the cutting 
edge for about two-fifths of the circumference, and no extension 
floors except those formed by sliding timber extensions which 
could readily be replaced without damage. 

After extensive tests on various makes of drills the Ingersoll- 
Rand " E-52 " 3 J-inch rock drill was adopted for this work. It 
was found to use less air than any other make and to stand up 
to the work equally well, if not better. These machines had 
exceptionally hard service on account of the seamy nature 
of the rock. They were generally mounted on standard drill 
columns set up in the pockets of the shields, except where 
advance headings were being driven. 

In addition to these standard rock drills a number of Ingersoll- 
Rand hand hammer or plug drills were used for trimming and 
breaking up lumps of rock. 

In the tunnels working under compressed air, no pumps 
were necessary in the air chamber, as the air pressure blew the 
water out from the pipes to the sump. It was possible under 
special circumstances, by allowing air to leak into the pipe 
from the chamber, for the water to be delivered right up into 
the river without the use of pumps. But generally it was found 
more reliable to blow the water from the tunnel to the shafts 
and to pump it from there. 

At the foot of each shaft, as a stand-by in the event of 
flooding, one special 6-inch vertical pump was installed capable 
of delivering 60,000 gallons per hour. Two Ajax drill sharpen- 
ers were used, one on the Manhattan side and the other at 
Long Island City.* 

There were two permanent shafts on each side of the East 
River and four single-track cast-iron tube tunnels, each about 
6000 feet long and consisting of about 3900 feet between shafts 
under the river and about 2000 feet in Long Island City, mostly 

* From ''Contractor's Plant for the East River Tunnels," by Henry Japp, 
M.A.S.C.E., in the Proceedings of the Am. Soc. C.E., November, 1909. 



126 SUBWAYS AND TUNNELS OF NEW YORK 

under the station and passenger yards of the Long Island Rail- 
road. An average of 1760 feet of tunnel was driven from Man- 
hattan, and 2142 feet from Long Island westward. Ground 
was broken on May 17, 1904. Five years later to a day, the 
work was finished and received final inspection for acceptance 
by the railroad company. 

The work was carried on from three sites, as follows : From 
permanent shafts located near the river in Manhattan, four 
shields were driven eastward to about the middle of the river; 
from two similar shafts at the river front in Long Island City, 
four shields were driven westward to meet those from Man- 
hattan; from a temporary shaft near East Avenue, Long Island 
City, the land section of about 2000 feet was driven westward 
to the river shafts. 

In the description which follows the cost of work will be 
given under two terms. " Unit labor " will be the cost of labor 
directly chargeable to the operation considered. " Top charges " 
will include the cost of the plant and its operation, the cost of 
the contractor's staff and roving labor, such as electricians, 
pipe men, yard men and all miscellaneous labor. But it does 
not include materials entering into the permanent work, or con- 
tractor's profit. 

Working east from the Manhattan shaft the formations 
were in succession as follows: 123 feet of all rock section; 87 
feet of all earth and rock; 723 feet of all earth section; 515 
feet of all earth and rock; 291 feet of all rock section; and 56 
feet of part rock and part earth. 

The rock was Hudson schist and Fordham gneiss. The 
latter was slightly the harder and both were badly seamed and 
fissured. When the rock surface was encountered it was cov- 
ered with a deposit of boulders, gravel and sand varying in thick- 
ness from 4 to 10 feet. The rock near the surface on the Man- 
hattan side was broken up and full of disintegrated seams; 
and it was irregular in stratification, dipping toward the west 
at about 60 degrees. The rock surface was very irregular and 
was covered with boulders and detached masses of rock bedded 
in coarse sand and gravel. From the latter material air escaped 



LOCKS IN NO.1 BUL 




FRONT ELEVATION 



DETAILS OF AIR-LOCKS 




CROSS-SECTION 
A-A 




n : ' 'i I - I m ■■■ ••' ■ ■ • ■ • ■ ' t ' ,, ' i 



SECTIONAL ELEVATION OF MAIN LC 




■Vo *^«} v^'v^^;^ i^i^^ -?;■■■ 



SECTIONAL ELEVATION OF MATERIAL LOCK-LOOKING SOI 

Bulkhead Construction, 



), TUNNEL A 




SECTIONAL ELEVATION 
ALSO INSIDE OF MATERIAL LOCK 



r*J5 




r r ' r 



OK IMG SOUTH 



DETAIL OF LOCK END 





DOOR A A 
CROSS-SECTIONS 
A-A,B-B 



% Red Lead 

Packing £-£,. Metal Waeher 



DETAIL OF HINGES 



Red Lead Washer 



Metal Washer 




DETAIL- SPLICE OF LOCK PLATES 

sylvania R.R. East River Tunnels. 















'" 



THE EAST RIVER TUNNELS 127 

freely. When the shields had entirely cleared the rock the 
material in the face had changed to a fine sand, stratified every 
few inches by very thin layers of chocolate-colored clayey 
material. This is elsewhere referred to as quicksand. As 
the shield advanced eastward, the number and thickness of the 
layers of clay increased until the clay formed at least 20 per cent 
of the entire mass, and many of these layers were 2 inches in 
thickness. About 440 feet beyond the Manhattan ledge, the 
material at the bottom changed suddenly to about 98 per cent 
clay. The sand layers were not more than ^ of an inch thick, 
averaging 2 inches apart. 

The surface of the sand and gravel was irregular but rising 
gradually. After rock was encountered the formations of 
rock and clay were roughly parallel to the rock surface ; as the 
surface of the rock rose they disappeared in order and were 
again encountered when the shields broke out of rock on the 
east side of BlackwelPs Island reef. East of the reef a large 
quantity of coarse open sand was present in the gravel forma- 
tion before the clay appeared below the top of the cutting edge. 
Wherever the clay extended above the top of the shield it reduced 
the escape of air very materially. 

While sinking the lower portions of the shafts the tunnels 
were excavated eastward in the solid rock for a distance of about 
60 feet, where the rock at the top was found to be somewhat 
disintegrated. This was as far as was considered prudent to 
go with the full-sized section without air pressure. At about 
the same time top headings were excavated westward from the 
shafts for a distance of 100 feet, and these headings enlarged 
to full size for a distance of about 50 feet. 

The shields were erected in the shafts, and were shoved 
forward to the face of the excavation. Concrete bulkheads 
with the necessary air-locks were then built across the tunnels 
behind the shields. The shields were shoved eastward for 
about 60 feet and the permanent tunnel lining erected as the 
shield advanced. Before leaving the rock, air pressure was 
necessary in the tunnels and this necessitated the building of 
bulkheads with air-locks inside the cast iron linings just east 



128 SUBWAYS AND TUNNELS OF NEW YORK 

of the portals. Before erecting the bulkheads it was necessary 
to close the annular space between the iron tunnel lining and the 
rock. 

The space at the portal was filled with the concrete wall. 
After about twenty permanent rings had been erected in each 
tunnel, two rings were pulled apart at the tail of the shield and 
a second masonry wall or dam was built. The space between 
the two dams was then filled with grout. To avoid the pos- 
sibility of pushing the iron backward, after the air pressure 
was put on, rings formed of segmental plates f of an inch thick 
and 13 J inches wide were inserted in 18 of the circumferential 
joints in each tunnel between the rings as they were erected. 
When these rings were in position they projected about 15 
inches beyond the alignment and when the tunnel was grouted 
they were bedded in the cement. The bulkheads were com- 
pleted, and the tunnels put under air pressure. In the deepest 
part of the river near the pier head line on the Manhattan side, 
there was only 8 feet of natural cover over the tops of the tunnels; 
and this was a fine sand which was certain to allow air to escape 
freely. A blanket of clay, averaging 10 or 12 feet in thickness 
was dumped over the line of work. It was found to be of 
material advantage, but its depth was insufficient to entirely 
stop the loss of air. 

The shields in each pair of tunnels were advanced through 
the solid rock section about abreast with each other, until the 
test holes from the faces indicated soft ground within a few 
feet. As the distance between the sides of the tunnels was 
only 14 feet, the two center tunnels were given a lead of 100 feet 
from this point as a precaution against a blow extending from 
one tunnel to another. 

When the shields in two of the tunnels in soft ground from 
Manhattan reached the bulkhead line, work was partly suspended 
and shutters put in place in the top and center compartments 
of the face of the shield. These shutters were moved in and 
out by screws on the ends of the shutters. Similar shutters had 
been used with marked success in loose open material in the 
Blackwell Tunnel. In operating, the shutters were forced by 




BACK ELEVATION OF SHUTTERS, SHOWING SLIDES 
FIG.7 




Method of Shield Driving, Pennsylvania 11. R. East River Tunnels. 



THE EAST RIVER TUNNELS 



129 



the screws against the face and material removed through the 
doors during the process. As pressure was applied to the shield 
jacks the shutters were allowed to slide back into the shield 
chambers, the screws being slacked back. In preparing for a 
new shove the slides in the shutters were opened and the material 
in front raked into the shield. 

No shutters were placed in the bottom compartments and 
as the air pressure was not generally high enough to keep the 




Rear of Shield showing Complete Fittings. 

face dry at the bottom, these lower compartments were pretty 
well rilled with a soft, wet quicksand. Much of the excavation 
in the bottom compartment was done by a blow-pipe. During 
the shove the material from the bottom compartment often 
ran back through the open door in the transverse bulkhead. 
In the Blackwell Tunnel, the material was loose enough 
to keep in contact with the shutters at all times. This was not 
the condition in the East River tunnels; the sand at the top 
was dry and would often stand with a vertical face for some hours. 



130 



SUBWAYS AND TUNNELS OF NEW YORK 



In advancing the shutters it was difficult to bring them in close 
contact with the face at the end of the operation. The soft 
material at the bottom was constantly running into the lower 
compartment and undermining the stiff material at the top. 
Under these circumstances, the air escaped freely through the 
unprotected sand face. The points of the shutters were plastered 
with clay, but this did not keep the air from passing out through 
the lower compartments. This condition facilitated the for- 




Shield Fitted with Fixed Hoods and Fixed Extensions to the Floors. 



mation of blowouts which were of constant occurrence where 
the shutters were used in sand. In one of the tunnels, the 
shutters were placed in the shield but never used against the 
face. Excavation was carried on by poling the top and breasting 
the face; and this change resulted in much better progress and 
fewer blowouts. 

Shutters were not placed on the Long Island shields. Before 
the shield entered soft ground a fixed hood was attached to 




PREPARING FOR SHOVE 

Fig. 1. 




| HT*" 



FINAL BREASTING OF MANHATTAN SHIELD 
Fig. 4. 



r — ■ r 



r tf 3 * 



r -iF" 1 




LONG ISLAND 



Method of Shield Driving, Pei 





AFTER SHOVE, ERECTING IRON 
FIG. 2. 



section:- shutters and breasting 
Fig. 3. 




\ : :V:d?- 



■ 90'+47.03 ~?* 
'.•;. .•-.••'^.'•90+49,6 



Fig. 5. 
«.nia R.R. East River Tunnels. 




MANHATTAN SHIELD 
FINAL POSITION 
SHOWING CONSTRUCTION OF BULKHEAD 



THE EAST RIVER TUNNELS 



131 



each. The face was mined out to the front of the hood and 
breasted down to a little below the floor of the top pockets of 
the shield. In the middle pockets the earth took a natural 
slope backward to the floor. In the bottom pockets it was held, 
at the back, by stop logs. The air pressure was always about 
equal to the hydrostatic head at the middle of the shield. In 
consequence, the face in the upper and middle pockets was 
dry, but in the lower pocket it was wet and flowed under the 




Shield Fitted with Sectional Sliding Hoods and Sliding Extensions to the 

Floors. 

pressure of shoving the shield. By this method, 4195 lineal 
feet of tunnel were excavated by the four Long Island shields in 
120 days between November 1, 1907 and March 7, 1908. This 
was an average of 8.74 feet per day per shield. 

Preparatory to making the final shove with the shields,, 
special polings were placed with unusual care. The Man- 
hattan shields were stopped and the excavation ahead made 
bell shape to receive the Long Island shields. The shields 
being shoved into final position, the rear end of the polings 
rested above the hood. When this was done, bulkheads of 



132 SUBWAYS AND TUNNELS OF NEW YORK 

concrete and clay bags were built to avoid blows when 
the shields came near each other. An 8-inch pipe was 
then driven forward to the bulkhead for from 30 to 100 feet, 
in order to check the alignment and grade between the two 
workings before the shields were actually shoved together. 
To bring the cutting edges together, it was necessary to cut 
away the projecting floors of the working compartments. 

Operations were carried on continuously for thirteen days 
out of fourteen, repairs being done on alternate Sundays when 
the work was closed down. When it was required to have an 
air pressure greater than 32 pounds, four gangs were worked, 
each gang working two 3 -hour shifts with 3 -hour intermission 
between shifts. When the air pressure was less than 32 
pounds three gangs were employed in three 8-hour shifts; 
J hour in low pressure was allowed for lunch. In soft 
ground during the greater portion of the work, the pressure 
maintained was about equal to the hydrostatic head at the 
axis of the tunnel. This was from 30 to 34 pounds per square 
inch above atmosphere. Pressures as high as 37 pounds were 
maintained for extended periods. In firm material 28 poimds 
was sufficient. While removing broken tunnel plates 42 pounds 
was carried for a short time; but pressures of from 37? to 40 
pounds were maintained for more than a month. 



CHAPTER XVI 

THE EAST RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

{Continued.) 

The river shafts on the Manhattan and Long Island sides 
were designed to serve as working shafts and permanent open - 
ings to the tunnels. As they were practically identical on both 
sides of the river, a description of the construction used in Long 
Island City will serve for both. There were two shafts on each 
side of the river, each shaft serving two tunnels. Each con- 
sisted of a steel caisson, 40 by 74 feet in dimensions with walls 
5 feet in thickness, filled with concrete. Each shaft was divided 
into two compartments, 29 by 30 feet, separated by a wall 6 
feet thick. Openings for the tunnels 25 feet in diameter were 
provided in the sides of the caisson, and these openings were 
closed during sinking by steel bulkheads. 

The shafts were sunk as pneumatic caissons to a depth of 
78 feet below mean high water mark. Most large caissons 
go to rock or a little below. The unusual feature of these caissons 
was that they were sunk 54 feet through rock. The roof of 
the working chamber was 7 feet above the cutting edge. Each 
chamber had two shafts, 3 by 5 feet in cross-section, with a 
diaphragm dividing it into two passages, one for men and one 
for the muck buckets. On top of these shafts were Moran 
locks. A 5-ton crane mounted on top of the caisson served both 
shafts and the muck cars on the ground level beside the caisson. 
Circular steel muck buckets 2\ feet in diameter and 3 feet high 
dumped the muck into the cars and returned to the bottom of 
the working chamber without unhooking. Work was carried 
on in three 8-hour shifts. 

On the Long Island side earth was excavated at the rate 
of 67 cubic yards per caisson per day. Rock excavation amount- 

133 



134 SUBWAYS AND TUNNELS OF NEW YORK 

ing to about 6200 cubic yards in each caisson was done at the 
rate of 44.5 cubic yards per day. The average rate of sinking 
through earth was 0.7 foot per day; through rock, 0.48 per day 
in the south caisson and 0.39 in the north caisson. In sinking 
the caissons 100- ton hydraulic jacks and wood blocking were 
used. When lowering, the air pressure was reduced by about 10 
pounds, which increased the net weight to more than 4,000,000 
pounds. The caissons usually carried a net weight of about 
870 tons. The concrete in them was generally kept about at 
the ground level. Water ballast 5 to 20 feet in depth was kept 
near the roof of the working chamber. The air pressure in 
the chamber was generally less than the hydrostatic head. 
For example, the average pressure in the caissons was 16 V 
pounds of air, while the average head was 62^ feet or 27 
pounds per square inch. The bottom of the shaft was an 
inverted concrete arch 4 feet thick, waterproofed with six-ply 
felt and pitch. 

The cost of excavation in the caisson was $15.02 per cubic 
yard, of which $4.48 was labor and $10.54 top charges. The 
cost of labor in compressed air chargeable to concreting was 
$3.40 per cubic yard. When the roof of each working chamber 
had been removed the shield was erected in a timber cradle in 
the bottom of the shaft, in a position to be shoved out of the 
opening in the side of the caisson. Temporary stays of iron 
lining were erected across the shaft to furnish an abutment for 
the jacks. 

The roof of the working chamber was re-erected about 
35 feet above its original position, bringing it about 8 feet above 
the tunnel openings. Instead of the two small shafts in use 
during the sinking of the caisson, a large steel T-shaped head- 
lock was built. This was 8 feet in diameter and contained a lad- 
der and elevator-cage for men and for standard i-yard tunnel 
cars. In the tee forming the top were two standard tunnel locks. 

On the Manhattan side the south shaft was sunk in earth 
at the rate of about 0.5 foot per day and the north shaft at about 
0.53 foot per day. Two 10-hour shifts were used. The average 
rate of excavation in soft material was 84 cubic yards per day; 



THE EAST RIVER TUNNELS 135 

in rock below the caisson, 125 cubic yards per day. Earth 
excavation cost $3.96 per cubic yard, of which $1.45 was for 
labor and $2.51 top charges. Rock excavation cost $8.93 per 
cubic yard, of which $2.83 was for labor and $6.10 for top charges. 

In driving tunnels westward from the Long Island shaft, 
the materials were encountered in the following order: 124 
feet of all rock section; 125 feet of earth and rock; 22 feet 
of all rock; 56 feet of earth and rock; 387 feet of all rock section; 
70 feet of earth and rock; and 1333 feet of all earth section. 
The rock was similar to that in the Blackwell's Island reef and 
was covered with sand and boulders. The soft ground was 
of three classes. The first was of fine red sand, occurring in 
layers from 6 to 15 feet thick. This is the quicksand usually 
found in deep foundations in New York City. With surplus 
water this sand is a true quicksand. When the water is blown 
out by air pressure it is stable, stands up well and is easy to 
work. The second material was known as " bull's liver/' 
consisting of thin layers of blue clay and of a very fine red sand. 
The clay was entirely free from sand. This was an ideal material 
in which to work a shield, as it stood up well, held the air about 
as well as clay and was much easier to work. The third material 
was a layer of very fine open gray sand which was encountered 
in the top of all the tunnels for about four hundred feet just 
east of Blackwell's Island reef. 

The first work in air pressure was to remove the shield plug 
closing the opening in the side of the shaft. This being done, 
the shield was shoved through the opening and excavation 
begun. The shields were fitted with movable platforms and the 
hoods were not placed until the rock excavation had been com- 
pleted. Shields had not been extensively used in rock up to 
this time and it was therefore necessary to develop methods 
of operation by experience. . When rock was present under the 
shields it was required that a bed of concrete be laid in the form 
of a cradle, upon which the shield was moved. Three general 
methods were used for excavating in the all rock sections — the 
bottom heading method, the full face method and the center 
heading method. 



136 SUBWAYS AND TUNNELS OF NEW YORK 

The bottom heading method was the first one tried. A 
heading 8 by 12 feet wide was driven on the center line, the 
bottom being at the grade line of the tunnel floor. Four drills 
were used, mounted on a column. The face of the heading was 
kept from 10 to 30 feet in advance of the shield. A concrete 
cradle, 8 to 10 feet wide, was laid when the heading had been 
driven 10 feet. The excavation was enlarged to full size as the 
shield advanced. The drills were mounted in the forward 
compartments of the shields, and the sides and top of the excava- 
tion were shot downward into the heading. As the heading 
was completely blocked by the material blasted from the face, 
work had to be suspended until the face had been mucked. 

The bottom heading method was as good as could be devised, 
with the shields equipped with two transverse bulkheads, as 
originally installed. All the muck had to be taken from the 
face by hand and passed through the chutes and doors. The 
closed transverse bulkheads were an obstacle to rapid progress 
in rock sections. These bulkheads with air locks were designed 
in the belief that it would be necessary to maintain the full 
air pressure in the working compartment only. In the case of 
blowouts it was thought that some form of bulkhead that could 
be quickly closed tight would be required to avoid flooding the 
tunnel. From experience gained while working in the sand from 
Manhattan to the Blackwell's Island reef, it was demonstrated 
that this design was not practicable, and that a bulkhead closed 
in the bottom was a hindrance. The bulkheads were cut through 
and altered to permit of the passage of cars through the shield. 

To avoid blocking the tracks when blasting and to permit 
working a larger force of men at the face, the level of the head- 
ing was raised. This reduced the quantity of rock to be taken 
from the top and the bottom was taken out as a bench. To 
keep the tracks clear while blasting, a timber platform was 
built from the center floor of the shield. The platforms were 
not entirely satisfactory and later the drills in the heading were 
turned upward and a top bench also worked. So little excava- 
tion was left in the top that the muck was allowed to fall in the 
tracks, from which it was quickly cleared. This method as 



D 



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CROSS-SECTION D-D 







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ENLARGING TO FULL SIZE CROWN BARS IN POSITION 




CROSS-SECTION B-B 
Fig.1 

MrllmJs of Excavation, Pennsylvania R.R. East River Tunnels, 



CROSS-SECTION C'-C 

DRIVING TOP HEADING 

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CROSS-SECTION L> it 



THE EAST RIVER TUNNELS 137 

outlined, called the center heading method, proved the most 
satisfactory for full rock sections. 

Excavation in earth and rock was the most difficult class 
of work encountered, particularly when the rock was covered 
with boulders and coarse, sharp sand which permitted a free 
escape of air. Before removing the rock under soft ground 
it was necessary to excavate the latter in advance of the shield 
to a point beyond where the rock was to be disturbed, and to 
support the top, sides and face of the opening thus made. A 
fixed hood attached to and in advance of the shield was designed 
to support the top and sides of the excavation. With this fixed 
hood it was necessary either to force the hood into the undis- 
turbed material, the distance required, or to excavate an opening. 
To avoid this difficulty sliding hoods were tried as an experiment, 
made in segments, which were forced forward by screw rods 
one at a time into the material as far as possible. Enough mate- 
rial was then removed from beneath and in front of the segment 
to free it when it was forced farther forward. These opera- 
tions were repeated until the section had been extended far 
enough for a shove. When the shield was advanced the nuts 
on the screw rods were loosened and the hood telescoped on the 
shield. Owing to the transverse strains on the hood section, 
caused by the unequal relative movements of the top and bottom 
of the shield in shoving forward, this plan proved impracticable. 

Fixed hoods were substituted for the sliding type and poling 
boards used to support the roof and sides, with breast boards 
for the face. In placing the poling and breasting, all voids 
behind them were filled with marsh hay or bags of sawdust 
or clay. To prevent loss of air in open material the joints between 
the boards were plastered with clay especially prepared in a 
pug mill for this purpose. 

When the rock face became sufficiently high and sound, a 
bottom heading was driven some 20 or 30 feet in advance of the 
shield, and the cradle placed. The remainder of the rock 
face was removed by firing top and side rounds into the bottom 
heading after the soft ground had been excavated. To avoid 
a run of material great care was taken in firing not to disturb 



138 SUBWAYS AND TUNNELS OF NEW YORK 

the timbering on the rock under the breast boards. In the 
early part of the work when a bottom heading was impracticable, 
the soft ground was first excavated as described above, and the 
rock was drilled by machines mounted on tripods and fired as a 
bench. By this plan no drilling could be done until the soft 
ground was removed. This was called the rock bench method. 
Later the rock cut method was devised. Drills were set up on 
columns in the bottom compartments of the shields and the 
face drilled while work was in progress in the soft ground above. 
This drilling was done either for horizontal or vertical cut, 
and side and top rounds. The drill runners were protected 
while at work by timber platforms built out from the floors 
of the compartments above. This plan, while not as economical 
of explosive, saved the delay due to drilling the bench. 

In driving the tunnels which connected the river shafts 
in Long Island City with East Avenue, a temporary shaft was 
sunk at East Avenue. This was rectangular in shape, built 
of rough 6 by 12 sheet piling, 127 by 34 feet. It was braced 
across by heavy timber and was driven about 28 feet to rock 
as the excavation progressed. Below this the shaft was sunk 
in rock about 27 feet without timbering. When the shaft was 
down, bottom headings were started westward in the tunnels. 
When these had been driven about half way to the river shafts, 
soft ground was encountered; and as the latter carried consider- 
able water it was decided to use compressed air. Bulkheads 
were built in the headings and with an air pressure of about 
15 pounds the heading was driven through the soft ground and 
into rock by ordinary mining methods. The use of compressed 
air was then discontinued. 

West of this soft ground the top heading followed by a 
bench was driven until soft ground was again encountered. 
One of the four tunnels, being higher, was more in soft ground. 
At first it was the intention to delay this excavation until it 
had been well drained by the bottom headings of the tunnels 
on either side; later it was decided to use a shield without 
compressed air. This shield had been used in excavating the 
stations of the Great Northern and City tunnel in London. 



THE EAST RIVER TUNNELS 139 

It was rebuilt, its diameter being changed from 24 feet 8 \ inches 
to 23 feet 5^ inches. But it proved too weak and after it had 
been flattened about 4 inches and jacked up three times, the 
scheme was abandoned, the shield removed and the work con- 
tinued by the methods employed in the other tunnels. The 
description of operations in one tunnel, therefore, will serve 
for all. 

From the bottom headings break-ups were started at several 
places in each tunnel where there was ample cover of rock. 
Where the roof was in soft ground top headings were driven 
from the point of break-up and timbered. As soon as the full- 
sized excavation was completed, the iron lining was built, 
usually in short lengths. At a point under the Long Island 
Railroad station the tunnels were in soft ground and to avoid 
disturbance of the surface a shield and compressed air were 
used. The shield was used to drive three of the tunnels, but 
during the driving it was found that the ground passed through 
was better than had been anticipated. There was considerable 
clay in the sand and after the water had been blown out by 
compressed air it was found to be very stable. The fourth 
tunnel was timbered and driven under air pressure without 
a shield. 

When the tunnel was all in good rock two distinct methods 
were used. The first was the bottom heading and break-up, 
and the second the top heading and bench method. The bottom 
heading, 13 feet by 9 feet high, having first been driven, a break-up 
was started by blasting down the rock to form a chamber of 
the full height of the tunnel. A timber platform was then 
erected in the bottom heading and extended through the break-up 
chamber. The plan was then to drill the entire face above 
the top heading and blast it down upon the timber staging. 
In this way the passage in the bottom heading was not inter- 
fered with. The spoil was loaded into cars in the bottom 
heading through holes in the staging. This method had the 
advantage that the bottom heading could be pushed through 
rapidly, and from it the tunnel could be attacked at a number 
of points at one time. It was found to be more expensive 



140 SUBWAYS AND TUNNELS OF NEW YORK 

than the top heading and bench method; and as soon as the 
depression of the rock was passed, a top heading about 7 feet 
high and roughly the segment of a 2 3 -foot circle, was driven 
to the next soft ground in each of the tunnels. The remainder 
of the section was taken out in two benches; the first, about 
4 feet high, was kept about 15 feet ahead of the lower bench, 
which was about 11 feet high. 

For a length of about 2500 feet of tunnel the roof was in 
soft ground and it was excavated in normal air pressure by 
the usual methods of mining and timbering. In the greater 
part of this, rock surface was well above the middle of the 
tunnel. Starting from the break-up in the all-rock section, 
when soft ground was approached the top heading was driven 
from the rock into and through the earth. This was done by 
the usual post, cap and poling board method, giving a heading 
about 7 feet high by 6 feet wide. The ground was a running 
sand with little or no clay and with considerable water in places. 
All the headings required side polings. The roof poling boards 
were about 2 \ or 3 feet above the outside limit of the tunnel 
lining. 

The next step was placing two crown bars, usually about 
20 feet long, under the caps. Posts were then placed under 
the bars, and poling boards at right angles to the axis of the 
tunnel were driven out over the bars. As these polings were 
being driven the side polings of the original headings were 
removed, and the earth mined out to the end of these new trans- 
verse polings. Breast boards were set on end under the ends 
of the transverse polings when they had been driven out to 
their limit. Side bars were then placed as far out as possible 
and supported on raking posts. These posts were carried down 
to rock, if it were near, otherwise a sill was placed beneath them. 

A new set of transverse polings was driven over these side 
bars and the process was repeated until the sides had been carried 
down to rock, or to the elevation of the sills supporting the 
posts, which were usually about 4 feet above the axis of the 
tunnel. The plan then was to excavate the remainder of the 
section and build the iron lining in short lengths, gradually 



THE EAST RIVER TUNNELS 



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142 SUBWAYS AND TUNNELS OF NEW YORK 

transferring the weight of the roof bars to the iron lining as the 
posts were taken out. Such workings were in progress at as 
many as eight places in one tunnel at one time. 

The plan adopted in one tunnel for driving in compressed 
air without a shield through soft ground, while not as rapid, 
proved to be as cheap as the work done by the shields. The 
operation of this scheme was as follows: Having the iron 
built up to the face of the full-sized excavation, a hole or top 
heading about 3 feet wide and 4 or 5 feet high was excavated 
about 10 feet in advance. This was done in a few hours with- 
out timbering of any kind. As soon as this heading was ten 
feet out, 6 by- 12 -inch polings were put up in the roof with 
the rear ends resting on the iron lining and the front ends on 
the vertical breast boards. The heading was then widened out 
rapidly and the lagging was placed down to about 45 degrees 
from the crown. The forward ends of the lagging were then 
supported by a timber rib and sill. Protected by this roof, 
the full section was excavated and three rings of iron lining were 
built and grouted; and then the whole process was repeated. 



CHAPTER XVII 

THE EAST RIVER TUNNELS OF THE PENNSYLVANIA RAILROAD 

{Continued.) 

As already stated, the specifications of the railroad company 
required an air compressor plant capable of supplying not 
less than 300,000 cubic feet of free air per hour at 50 pounds 
pressure above normal atmosphere to each heading, and a reserve 
plant of 25 per cent of this capacity. The air compressor 
plants on each side of the river, installed by the Ingersoll- 
Rand Company of New York, met these requirements, having 
a rated capacity of 25,000 cubic feet of free air per minute or 
an average of 5260 cubic feet per minute per heading. 

In tunnels B, C and D the shields broke through rock sur- 
face in November and December, 1905. The air consumption 
in the four tunnels exceeded 15,000 cubic feet, and in tunnel 
D alone on several occasions it exceeded 7000 cubic feet per 
minute for twenty-four hours. Blows had been frequent and 
it was evident that a greater volume of air would be required 
than was anticipated in order to drive the four tunnels simulta- 
neously in the open material east of the Manhattan rock. Work 
was accordingly suspended on two of the tunnels while the rated 
capacity of the compressing plant was being increased from 
25,000 to 35,000 cubic feet of free air per minute. 

During one period of the work one, and sometimes two, 
tunnels were shut down. The consumption of air in the tunnels 
from Manhattan averaged more than 20,000 cubic feet per minute 
for periods of from 30 to 60 days. It was often more than 25,000 
cubic feet per minute for twenty-four hours, with a maximum 
of nearly 29,000 cubic feet. On several occasions the quantity 
supplied to a single tunnel averaged more than 15,000 cubic 
feet throughout a 24-hour period. The greatest average for 
twenty-four hours was in excess of 19,000 cubic feet per min- 

143 



144 SUBWAYS AND TUNNELS OF NEW YORK 

ute ; but conditions were so favorable in the other headings at this 
time that work could be carried on continuously in all of them. 

The need of driving all headings simultaneously from the 
Long Island side was so evident that it was decided to increase 
the rated capacity of the Long Island City plant to 45,400 
cubic feet of free air per minute, which was 10,400 cubic feet 
in excess of the augmented Manhattan plant. 

The earth encountered on emerging from the rock when 
driving westward from Long Island was far more compact and 
less permeable to air than on the Manhattan side. But for a 
distance of from 400 to 600 feet immediately east of the reef 
a clean, open sand was met, and while the shields were passing 
through this the quantity of air supplied to the four headings 
was seldom less than 20,000 cubic feet per minute; it was 
usually more than 25,000 cubic feet, with a recorded maximum 
of 33,400 cubic feet. This was a greater volume than was ever 
used on the Manhattan side and it was more uniformly distrib- 
uted among the several headings. In no case, however, did 
the air consumption per heading equal the maximum observed 
on the Manhattan side, the largest on the Long Island side 
being 12,700 cubic feet per minute for twenty-four hours. It 
is to be remembered that at one time only two tunnels were in 
progress in the bad material, working eastward from Manhattan. 

It would seem that a reasonable compliance with the actual 
needs on the Manhattan side would have been an air compressing 
plant of a rated capacity of 45,400 cubic feet per minute, and on 
the Long Island side one of a capacity of 35,000 cubic feet per 
minute. 

The total quantity of free air compressed for the supply 
of the working chambers of the tunnels and the Long Island 
caissons was 34,109,000,000 cubic feet. In addition 10,615,000,000 
cubic feet were compressed to between 80 and 125 pounds for 
power purposes, of which at least 80 per cent was exhausted in 
the compressed air working chambers. The total supply of 
free air to each heading while under pressure, therefore, averaged 
about 3550 cubic feet per minute. 

Investigation of the number of blowouts showing large 



THE EAST EIVER TUNNELS 145 

losses of pressure and with the relatively large reservoir capacity 
provided by the long stretch of tunnels, a maximum loss of 
220,000 cubic feet of free air was known to occur in ten minutes. 
Of this quantity, however, probably 30 or 40 per cent escaped 
in the first forty-five seconds, while the remainder was a more 
or less steady loss up to the time when the supply could be 
increased sufficiently to maintain the lower pressure. Very 
few blows showed losses approaching this in quantity, and in 
this particular case the inherent inaccuracies of the observa- 
tions make the figures only a rough approximation. 

A clay blanket covering the open materials penetrated by 
the tunnels was essential throughout the work. The material 
used in this blanket amounted to 283,412 cubic yards, of which 
117,846 cubic yards were removed from over the completed 
tunnels and re-deposited in advance of the shields. A total 
of 88,059 cubic yards of clay was dumped over blowouts. 
The total cost of placing and removing the clay blanket was 
$304,056. 

The standard cast-iron tunnel lining was of the usual tube 
type 23 feet in outside diameter. The rings were 30 inches wide 
and were composed of eleven segments and a key. The webs 
of the segments were ij inches thick in the central portions 
and increased to 2§ inches at the flanges which were 11 inches 
deep and machined on all contact faces. Bolt holes were cored 
in the flanges. The segments weighed about 2020 pounds 
each and the key 520 pounds. The weight of the iron per foot 
of tunnel was 9102 pounds. 

The tube of iron rings was adapted to be built in the tail 
of the shield. Where no shield was used, after the excavation 
was completed and all loose rock removed, timbers were fixed 
across the tunnels from which semicircular ribs were hung, 
below which lagging was placed. The space between this and 
the rough rock surface was filled with concrete forming a cradle 
in which the iron tube could be erected. At the same time it 
occupied a space that would have had to be filled with grout 
at a greater cost had the shield been used. These concrete 
cradles averaged 1.05 cubic yards per foot of tunnel and cost, 



146 



SUBWAYS AND TUNNELS OF NEW YORK 





SECTION SHOWING FORMS 
FOR INVERT 
FlG.l 




SECTION SHOWING FORMS 

FOR BENCH 
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SECTION SHOWING ARCH FORMS 

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it.R. East River Tunnels. 



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'ennsylvania R.R. East River Tunnels. 



THE EAST RIVER TUNNELS 147 

exclusive of material, $6.70 per cubic yard, of which $2.25 was 
for labor and $4.45 top charges. 

As soon as each ring was erected, the space between it and 
the roof of the excavation was filled with hand-packed stone. 
The interstices between the hand-packed stones were then rilled 
with 1 -to- 1 grout of cement and sand injected through the iron 
lining. The hand-packed stone averaged i| cubic yards per 
foot of tunnel and cost $2.42 per cubic yard, of which $.98 was 
for labor and $1.44 for top charges. 

It was planned to erect the iron lining with erectors of the 
same type as those used in the iron shields, but mounted on 
a traveling stage. There were two erectors, but as the tunnel 
was being worked at so many points this number was inadequate 
to meet the requirements. As a result about 58 per cent of the 
lining was done by hand. A portable hand winch was used for 
handling and placing the segments. The cost of erecting by 
hand was no greater than by the erectors. This was due to 
the greater power and plant charges against the erectors and 
to the fact that they were not in constant use. 

The total amount of grout used on the work was, in set 
volume, equivalent to 249,647 barrels of i-to-i Portland cement 
grout, of which 233,647 barrels were injected through the iron 
lining. The average was 19.93 barrels per lineal foot of tunnel. 
The cost of the grout injected outside of the iron tunnel was 
$.93 per barrel for labor and $2.77 for top charges. East of the 
Long Island shaft the corresponding costs were $.68 and $1.63, 
the difference being partly due to the large percentage of 
work done in normal air. 

Joints were at first caulked with a mixture of iron filings 
and sal ammoniac in the proportions by weight of 400 to 1, 
caulked by hand. Later, lead wire caulked cold by pneumatic 
hammers was substituted. The average cost of labor was $.12 
per lineal foot and top charges $.218. All concrete was placed 
under normal air. The cost of labor chargeable to concrete 
was $1.80 per cubic yard and top charges were $3.92 exclusive 
of the cost of materials. 

From Proceedings of the American Society of C. E., October, 1909. 



CHAPTER XVIII 
THE BELMONT TUNNELS 

The various tunnel and subway undertakings which are 
to vastly increase the transit facilities of Greater New York, 
are quite different from each other in the conditions and means 
of construction, and each has imposed special engineering 
problems to be solved. Not the least interesting was the work 
on the Belmont tunnels under the East River which are now 
completed, but at the time of writing are not yet in actual 
operation. 

The Belmont system includes a tunnel and subway over 
three miles in length, extending from* Park Avenue and Forty- 
second Street, Manhattan Island, to Jackson Avenue and 
Fourth Street, Long Island City. It will afford easy and quick 
transit between the Borough of Queens and Manhattan and will 
probably connect with some of the transit systems in New York 
City near the Grand Central Station. The first shift was started 
in July, 1905 and work was rushed continuously and with great 
vigor night and day until completion. The system consists 
of two single-track parallel tunnels. Part of the tubes are 
horseshoe shaped, while under the river they are of circular 
section and built of sectional cast iron rings. The contractors 
were the Degnon Engineering and Construction Company. The 
builders had an advantage as to time of construction, in that 
the tunnels could be driven from four headings instead of two, 
or, as in the case of the Cortlandt Street tunnel, from a single 
heading. 

For driving the subaqueous tunnel from its western end 
and for the construction of the subway westward from Forty- 
second Street there were two separate compressed air instal- 
lations, resulting from certain business arrangements. The 

148 



THE BELMONT TUNNELS 



149 



plant of the O'Rourke Engineering Company which was sold 
to the Degnon Company included the following equipment: 
One Ingersoll-Rand cross-compound Corliss steam, 2 -stage air 
compressor with steam cylinders, 24 and 40 inches in diameter, 
air cylinders 39 and 24 inches, stroke 48 inches and a free air 
capacity of 4147 cubic feet per minute; one Ingersoll-Rand 
cross-compound Corliss steam, 2-stage air compressor with steam 




Long Island City Air Compressor Plant, Belmont Tunnels. 

cylinders 22 and 40 inches, air cylinders 38 and 24 inches, stroke 
42 inches and a free air apacity of 3937 cubic feet per minute. 

The Degnon Contracting Company's plant at the same 
point included three Ingersoll-Rand cross-compound steam, 
duplex air compressors with steam cylinders 15 and 28 inches, 
air cylinders 2oi inches, stroke 16 inches, a free air capacity 
of 6540 cubic feet per minute and a maximum air pressure of 
50 pounds. There was also one Ingersoll-Rand cross-compound 
steam, 2-stage air compressor with a steam end identical with 



150 SUBWAYS AND TUNNELS OF NEW YORK 

the above machine, but with compounded air cylinders 25^ 
and i6j inches in diameter, a free air capacity of 1704 cubic 
feet per minute and air pressure 100 pounds. 

The most interesting in some respects of all the New York 
tunnel plants was that installed by the Degnon Contracting 
Company upon Man-O'-War's Reef in the middle of the East 
River, opposite Forty-second Street. The existence of this 
reef made possible the sinking of two shafts, giving four addi- 
tional working faces for the two sub-river tunnels. The first 
thing to be done was to get floor space, as the original area wes 
entirely insufficient. At first a single Ingersoll-Rand straight 
line compressor with a portable boiler was installed and the 
sinking of the two shafts was begun. The material from these 
shafts was used for filling upon and around the reef until a 
sufficient area was secured for the installation of the complete 
plant, but with not a square foot of space to spare. The com- 
pressor room extended to the water's edge on two sides with 
but a small space on the New York side; while to the north 
enough land was made to provide for the moving of muck 
cars to scows on either side. 

The power plant equipment used here included one Ingersoll- 
Rand straight line, steam driven compressor with 24-inch 
steam cylinder, 261-inch air cylinder, 30-inch stroke and a free 
air capacity of 1843 cubic feet per minute. In addition to this 
steam driven unit there were four electrically driven, belted, 
duplex compressors built by the Ingersoll-Rand Company. 
Three of these had duplex air cylinders 20} inches in diameter 
by 16-inch stroke with an aggregate free air capacity of 6540 
cubic feet per minute. The fourth machine was a 2-stage com- 
pressor with air cylinders 25J and 161 inches in diameter, 16-inch 
stroke and a free air capacity of 1704 cubic feet per minute. 
This latter machine delivered air at 100 pounds pressure while 
the three other power driven units carried 50 pounds air pressure. 
These motor driven units were to run at constant speed, the air 
delivery being regulated by choking controllers on the intake. 
One straight line steam driven compressor was included in 
this plant, but is not shown in the illustration. The current 



THE BELMONT TUNNELS 



151 



for the electric motors was taken from a cable connecting with the 
Manhattan lines of the Interborough Company. The elevators 
in the two shafts were also driven by electric power from the same 
source. Locomotive boilers supplied steam for the two straight 
line machines, the feed water being piped from Manhattan. 

While this plant, on account of its location and of its for- 
bidding accompanying conditions, might have been regarded 
as more or less an emergency plant, it must not be thought 




Man-O'-War's Reef Air Compressor Plant, Belmont Tunnels. 

to have been a wasteful one. The electrically driven machines, 
taking their current from a service in which the highest possible 
economies are attained, and having motors especially adapted 
to their work, delivered their air at a lower cost than the straight 
line steam driven machines, notwithstanding the fact that the 
latter represented practice still widely prevalent. 

In the Long Island City plant there were in service two 
Ingersoll-Rand cross-compound steam, 2-stage air compressors 



152 SUBWAYS AND TUNNELS OF NEW YORK 

with steam cylinders 15 and 28 inches in diameter, air cylin- 
ders 25 \ and 161 inches, 16-inch stroke and a free air capacity 
of 3408 cubic feet per minute at 100 pounds pressure. There 
were also two Ingersoll-Rand straight line, steam driven com- 
pressors, 24 and 26! by 30 inches in dimensions, with a free air 
capacity of 3686 cubic feet per minute; and one Ingersoll- 
Rand machine of the same type, 24 and 24! by 30 inches, 
free air capacity 1570 cubic feet per minute. These last three 
units were low pressure compressors and were supplied with 
steam by Heine boilers. 

While the pneumatic pressure maintained in the tunnels 
until completion was always equal to, or somewhat in excess 
of, the hydrostatic pressure due to the submergence, there was 
a constant accumulation of water in the workings. While the 
air pressure would be in excess of the water pressure at the top 
of the shield, it might still be insufficient at the bottom; and 
here the water entered. This was collected in temporary 
sumps in the air-locks from which it was forced out by air pres- 
sure through pipes to various pumping stations situated along 
the line of construction. There was also a constant seeping 
of water through the joints where the caulking had not been 
completed. The sumps were situated where the grade was 
the lowest and at these points the pumps were located, lifting 
the water to the surface or directly into the river; or, in the 
land sections, into sewers connecting with the river. 

In several places the segments or wall plates were removed 
and the material forming the 8-foot partition between the two 
tubes was cut away to provide sump chambers and to allow 
room for the pumps. 

Where the pumps were situated alongside the tunnel walls 
and in the workings, no extra room was required for their 
installation, as these pumps were all of the Cameron type, 
with their well-known and characteristic lack of protuberant 
parts. 

The Cameron pumps were particularly well adapted for use 
in tunnels or other restricted quarters, or in situations exposed 
to flooding, or falling rock or debris from blasting or excavation. 



THE BELMONT TUNNELS 



153 




Battery of Cameron Pumps installed in " Belmont " Tunnel, under East 
River, under Man-O'-War's Reef. 



They had no outside valve gear or moving parts to be deranged 
or broken by passing cars or falling material. They were reliable 
under all conditions, and in cases of sudden flooding would work 
as well when submerged to any depth as under normal condi- 
tions. In case of accident or emergency they could be run up 
to double their normal capacity. 

A simple device was attached to the pumps to keep the 
exhaust compressed air from freezing and choking the passages. 
A small pipe was connected from the water discharge pipe to 
the exhaust openings of the air operated cylinder, and through 
it a f-inch nozzle discharged constantly when the pumps were 
running. This not only prevented freezing, but also had the 
effect of a muffler on the exhaust. These pumps were driven 
by compressed air, as were also the drills and the hoisting and 
other machinery employed. — Frank Richards, in Compressed Air 
Magazine. 



CHAPTER XIX 

THE HUDSON-MANHATTAN TUNNELS 

As stated in an early chapter of this book, De Witt C. Haskins 
began the construction of a brick walled tunnel under the 
Hudson River a third of a century ago. One great accident 
entailing serious loss of life led to legal and financial difficulties 
which paralyzed the undertaking. In 1902 the New York 
and New Jersey Railroad Company resumed serious work on 
the tunnel. In the following year this company was merged 
with the Hudson-Manhattan Railroad Company; and later 
the Hudson Companies were formed to conduct the construc- 
tion and real estate operations involved. It was estimated 
that the entire project when completed would cost $70,000,000. 

The accompanying map of this system makes clear its route 
and shows its ramifications and connections. The system 
as a whole may be considered as made up of four sections. The 
twin tubes from Hoboken, N. J. near the D. L. & W. terminal, 
under the river to Sixth Avenue, New York City, enter Man- 
hattan two blocks below Christopher Street and pass up 
through Sixth Avenue to Thirty-third Street near the Penn- 
sylvania Railroad terminal. The south twin tunnels, which 
may be called the second section, were driven entirely from 
the Jersey side of the river, passing from the terminal of the 
Pennsylvania Railroad in Jersey City, under the river and 
entering Manhattan Island at Cortlandt Street. 

At Jersey City a large terminal station was hewn out of the 
solid rock, 85 feet below the present station of the Pennsylvania 
Railroad. The tunnel station here is 150 feet long with 
approaches 1000 feet in length, and is equipped with large pas- 
senger elevators to the surface. The Manhattan terminal is 

155 



156 SUBWAYS AND TUNNELS OF NEW YORK 

surmounted by the Hudson Terminal buildings, two of the 
largest office buildings in New York City. 

The third section is a land tunnel parallel with the Hudson 
River, connecting the Hoboken terminal with that in Jersey 
City and commanding the passenger stations to four trunk 
railroad lines which were formerly entirely dependent on ferry 
service for New York connection. The fourth section is a land 
tunnel running from the Jersey City terminal under the Penn- 
sylvania Railroad Station toward Newark. This passes under 
the most crowded portion of Jersey City, coming to the surface 
at the outskirts; and the tunnel trains from this point will 
use the Pennsylvania Railroad tracks to the transfer station 
at Harrison and thence to Newark, N.J. It will be noted that 
more than one-half of this entire system is land tunnel or, in 
Sixth Avenue, typical subway involving generally no unusual 
difficulties. The river work, however, presented unusually 
difficult engineering problems. The employment of compressed 
air as a plenum and for operating the drills, shields and other 
mechanism used in construction was the essential condition 
which made it possible to bring these tunnels to successful 
completion. 

Messrs. Charles M. Jacobs and J. Vipond Davies were 
placed in charge of the engineering when the project was taken 
up anew by the Hudson Companies. The north tunnel had 
then been driven 3800 feet from the Jersey side. The shield 
previously used in this work was retained in service, but 
with necessary changes to adapt its use to a spur of rock then 
being approached which would require to be drilled and blasted 
in advance of the shield. A heavy hood or apron extending 
6 feet on the upper half was added to the shield to afford pro- 
tection to the laborers while working in the rock. At this point 
work was carried on under an air pressure of 33 pounds, there 
being 14 feet of silt and 65 feet of water above the shield. At 
places where blows occurred the river bed was covered with a 
clay blanket before operations could be continued. 

In beginning the south tunnels, changes were made in the 
design of the tunnel and in the mode of procedure. The size 



THE HUDSON-MANHATTAN TUNNELS 157 

was reduced to a diameter of 15 feet 3 inches in the clear. Cast 
plates bolted together insured a true circular section and the 
shield could be manipulated to follow the alignment. A 
hydraulic erector was carried by the shield for placing the 
lining plates or sections in position for bolting. 

The forward movement of the shield was controlled by 
hydraulic jacks exerting an aggregate thrust of 2500 tons. It 
was found that the shield could be thrust forward, displacing 
the silt without excavating in front of the shield. Because of 
this quality in the silt the cost of construction became less than 
ever before attained in this class of work. Five feet of advance 
was considered good progress per twenty-four hours where 
the material was required to be removed from in front of the 
shield before shoving. On the other hand, 72 feet of progress 
was made in twenty-four hours in the Cortlandt Street tunnels 
where the material was displaced by the shield. 

In an address by Mr. Jacobs, Chief Engineer, before the 
Yale Club of New York, the following description of some of the 
contingencies of subaqueous tunneling was given. 

" At the beginning of the work on the south tube of the 
uptown tunnel, the shield from the Hoboken side was being 
advanced through the silt with the shield doors closed so as to 
save the cost of excavation. While the headings were still 
under the Lackawanna coal dock, the night superintendent, 
thinking that the shield was moving very slowly, determined 
(contrary to orders) to open one of the center doors so as to let 
the mud come in and so let the shield go ahead faster. 

" The silt shot in under such pressure that it buried some 
of the workmen before they could escape; the rest of the shift 
got away through the upper emergency lock which was then 
115 feet away from the shield face. The heading was lost, and 
the tunnel between the shield and the lock was filled solid with 
mud. The coal dock was crowded with shipping and, further- 
more, the Lackawanna at that time was not particularly favorable 
to the tunnel enterprise, so that it would have been almost 
impossible to get permission to dredge out the bed of the river 
in front of the shield so that a diver could go down and timber 



158 SUBWAYS AND TUNNELS OF NEW YORK 

up the exterior opening of the doorway. The problem was 
solved as follows: 

" Two heavy mainsails were procured and a double canvas 
cover about 60 by 40 feet made of them. Around the edges 
were secured small weights of pig iron. The canvas was 
spread on a flat barge and lines carried to fixed points to 
hold the mainsail in position. The barge was withdrawn and 
the mainsail allowed to drop to the bed of the river, 30 feet 
of it covering the shield and the remaining 30 feet extending 
out beyond the face toward the middle of the river. One of 
the pipe valves in the lock was then opened and the mud, 
under the direct pressure of the river, shot into the tunnel 
westward of the lock for 40 feet. It came in a solid stream 
for eight days and nights. Finally it let up for a few minutes, 
began again and then stopped. 

" A cavity had been formed in the bed of the river outside 
the cutting edge of the shield into which the canvas dropped 
and was eventually drawn into the opening of the doorway 
through which the mud was pouring. A small cavity was 
excavated in the mud-filled tube ahead of the lock and, the air 
pressure being put on, it immediately relieved much of the 
strain on the temporary canvas cover. Miners were then able 
to get into the tunnel and dig out the mud. In about nine 
days the heading was recovered and the door on the inside 
closed. 

" The north tube is an extension of an old tunnel abandoned 
some years ago. Within 100 feet from the point where the 
shield stopped in the previous attempt was a reef of rock, stand- 
ing from 1 to 16 feet above the intended grade of the tunnel. 

" Before the shield arrived at this point, it was necessary 
to build a temporary workshop in the river ahead of the shield, 
so as to build on the front of it a steel apron under which the 
men could work in drilling the rock and blasting it out of the 
path of the shield. Above the rock was soft silt and, above 
that, from 60 to 65 feet of water. It was expected that in blast- 
ing the rock with so slight a cover, and with such a heavy water 
pressure, the heading would probably be blown out. 



THE HUDSON-MANHATTAN TUNNELS 159 

" Clay loaded on barges was, therefore, always held in 
readiness to be dumped into any such blowout. After a few 
weeks the expected blowout occurred and the 900 feet of tunnel 
from lock to heading was flooded. The men at work escaped. 
The clay scows were immediately brought over the blowout 
and dumped, thus blocking the hole. The water was pumped 
out into the western workings, and within eleven hours men 
were able to reach the headings on a small raft. No damages 
were found and work was soon again under way. In all, only 
twenty-one hours of time were lost. There were two more 
blowouts while the tunnel was being built across the 700 feet 
of reef, and in each case they were similarly dealt with. 

" Finally, however, there was a problem which could not be 
dealt with by dropping these clay blankets. At the extreme 
eastern end of the reef the rock rose about 16 feet above the 
bottom of the cutting edge of the shield. The tunnel at this 
point is so near the bottom of the river that the clay was almost 
fluid and continually slipped into the pockets of the shield, 
so that the men could not get out underneath the apron to 
drill the rock. Scow after scow was dumped but the clay would 
not hold. 

" Finally, blow-pipe flames, fed from two tanks of kerosene, 
were directed against the exposed clay until it was indurated, 
so as to hold its position while the men drilled the rock. The 
blow-pipe process took eight hours, during which time streams 
of water were continually played on the shield structure to pre- 
vent it being damaged by the high temperature. This is probably 
the first time that man has made brick in the bottom of a river." 



CHAPTER XX 

THE HUDSON-MANHATTAN TUNNELS {Continued) 

Wherever work was executed by open-cut methods the 
structure was waterproofed with fabric and pitch applied in 
the usual manner, making a complete envelope around it. 
As the greatest part of this work, however, was executed 
by tunnel methods this manner of waterproofing was not 
feasible, except in small portions of the work. The method 
adopted, therefore, was invariably to grout with Portland 
cement in the rear of the plate lining or concrete lining, 
and in the majority of cases this application answered the 
purpose of making the tunnels perfectly watertight. Owing 
to the impervi ousness of neat cement this was the only water 
proofing adopted on the coffer-dam walls of the Church Street 
terminal and approaches. 

In the iron-lined sections of tunnel all joints of the plate 
segments were first grummetted on the bolts with flax and red 
lead under the bolt washers, and caulking spaces between the 
joints of the plate lining were first caulked with a thread of lead 
wire, followed up and supported with rust joint cement. Through- 
out the concrete work, waterproofing was done by plastering 
the internal and exposed surface with one of the usual types 
of waterproofing compounds mixed with neat Portland cement 
and applied with a trowel, this method answering admirably 
in a majority of cases. At the same time, in persistent leaks, 
it was found necessary to cut right back into the concrete and 
expose the voids and then reconstruct such portion of concrete 
with a rich mixture of cement. As a general rule, for water- 
proofing of concrete work a rich mixture of cement in the con- 
crete with thorough and efficient ramming answered the pur- 
pose and constituted the only waterproofing used. 

160 



THE HUDSON-MANHATTAN TUNNELS 



161 



Generally speaking, the standard track throughout all the 
lines of the company consists of white oak ties, laid in broken 
trap rock ballast on a flat surface of concrete forming the invert. 
This concrete invert fills the flanges between the plates in the 
tube tunnels and a drain is formed with a reinforced concrete 
slab over the same along the center line of the tunnel, which 
provides efficient drainage of the tunnel. 




Interior of Hudson-Manhattan Tunnel. 

The rails are 85-pound A.S.C.E. section with continuous 
rail joints, and all rails are attached to the ties with screw spikes 
of special design for this company's work. Goldie tie plates are 
used throughout, the plates being put on the ties under hydraulic 
pressure before the ties are sent into the tunnels, the plates 
being put into exact template spacing. Holes in the ties for 
the screw spikes were bored with a pneumatic auger before the 
ties were taken into the tunnels, and the screw spikes put in 



162 SUBWAYS AND TUNNELS OF NEW YORK 

place and driven with a pneumatic screw driver which proved 
very rapid in operation and of great efficiency. This tool was 
designed by officers of the company for the particular use to 
which it was put. 

All the rail used in the downtown tunnels has been 0.90 
per cent, carbon manufactured by the open hearth process by 
the Bethlehem Steel Company; and on heavy curves either 
chrome nickel or manganese steel rail was used, according to 
the radius of curvature. 

The contact (third) rail is of special type, designed by 
L. B. Stillwell, the company's consulting electrical engineer. 
This rail is carried on heavy porcelain insulators and secured 
by pressed steel brackets to long ties spaced about 10 feet apart. 
The contact rail is protected by an overhanging board of Aus- 
tralian jarrah wood. 

At heavy curves and in the downtown terminal, as well as 
at special points where reinforcing was executed, the track was 
laid in solid concrete. 

Guard rails are installed on all curves of less than 750 feet 
radius, these rails being 100-pound section A.S.C.E. and tb 
inches higher than the running rail. All frogs and switches 
are of manganese steel. 

In Jersey City and Hoboken where the various tunnels of 
the several routes make connections between Jersey City, 
Hoboken and uptown New York, the elimination of grade cross- 
ings was essential to the design of the work, and to meet these 
conditions the tunnels were superimposed. This operation 
necessitated the construction of junctions in the tunnels, all of 
which, unfortunately, came at locations where the construction 
would be in loose sand or other soft foundation in which grave 
difficulties would have been involved in making the enlarge- 
ments entirely by underground methods. 

The enlargement at the junction of Sixth Avenue and Ninth 
Street was carried out entirely by underground methods on 
account of the conditions of traffic on the streets above, which 
would have made open-cut methods very difficult and have 
caused grave inconvenience to the public. This junction was 




Construction of Tunnel Cra 




r, Hudson-Manhattan Tunnels. 



THE HUDSON-MANHATTAN TUNNELS 163 

constructed in sand formation overlying the rock, and as the 
location was in part on the site of a former creek there was a 
good deal of quicksand present to be taken care of. The entire 
work therefore, had to be executed under air pressure. At 
this point the shields in the two diverging lines were carried 
through continuously, forming the external lines of the enlarge- 
ment; and these tubes so constructed were used to brace from, 
in constructing the enlargement. 

Sections of lining plates were take out from the sides of 
these tubes and tunneling carried on between the tubes for 
the insertion of the heavy timbering put in place to carry the 
roof, maintaining the breast throughout and carrying the work 
on in section lengths. In this way excavation was carried on 
and the arch forming the permanent lining put in place in short 
lengths but of the full structure width, having in part a clear 
span of 60 feet. This work was executed with only a very 
slight settlement of the surface of the ground. At the same 
time columns of the elevated railway structure overhead were 
supported by long girders wedged to brackets riveted to the 
columns and constantly watched to take up any settlement 
which might occur. This method of underground enlargement 
(see page 156) was necessarily very expensive, and to execute 
similar work in the three different sites on the Jersey side, each 
of which was of greater dimensions than the enlargement at 
Sixth Avenue and Ninth Street, made a careful detail study of 
the possibilities desirable. 

In Jersey City, fortunately, the three junction enlarge- 
ments involved came below properties occupied by the Delaware, 
Lackawanna & Western Railroad and the Erie Railroad for yard 
purposes ; and by arrangement with these companies the surface 
of the ground was occupied for the purpose of carrying on the 
work. In all these cases the foundations could be carried to rock. 

These enlargements were made by caissons sunk from the 
surface. It was proposed to use concrete lined steel caissons 
but owing to the high cost and the time required for delivery 
of the steel, a reinforced concrete design was adopted which 
permitted the immediate commencement of work and at a much 



164 



SUBWAYS AND TUNNELS OF NEW YORK 



lower cost for the caisson. Three caissons fitted with locks and 
other necessary equipment were built on the ground and sunk 
from the surface, as in bridge pier practice. Where the tunnel 
tubes were to enter the caissons, concrete dummy drum heads 
were built, which were removed when the proper elevation was 




Arrangement of Branch Tunnels and Cross-over on New Jersey Side, 
Hudson-Manhattan Tunnels. 

reached; and shields were erected for the commencement 
of the tunnels from the caissons. In other cases shields drawn 
from other points were aligned to connect at the drum heads 
where the points were sealed with the tunnel lining before 
removing the drum heads. 



THE HUDSON-MANHATTAN TUNNELS 165 

The sizes of caisson Nos. i and 2 were 23 feet 5^ inches to 
45 feet 8 inches in width by 101 feet 2 inches in length by 51 
feet in height. Caisson No. 3 was 106 feet long, 45 feet wide and 
43 feet n£ inches high. This caisson was arranged with eight 
tunnels, as follows: At the north end, two superimposed to and 
from Hoboken, and two superimposed to and from New York, 
and on the south end two superimposed tunnels to and from 
New Jersey and two superimposed tunnels to be used in the 
future when connection is made with the Erie tracks. The 
caisson was sunk 85 feet below tide level. Its total weight 
was about 10,000 tons.* 

Perhaps the greatest feat in construction was the building 
of the tunnels at the intersection of Christopher Street, Ninth 
Street and Sixth Avenue, Manhattan. From this point two 
tunnels run east under Ninth Street and two north under Sixth 
Avenue. Here there was the elevated railway overhead, the 
Metropolitan Street Railway lines on the street surface, and 
buildings on each side of the street. This made the problem 
similar to the intersections in Hoboken, except that in this case 
the sinking of caissons was out of the question. 

To accommodate two tubes coming up from the south and 
the four diverging to the east and north, it was necessary to 
build an arch of which the maximum width was 68 feet. The 
work was all in running sand and of necessity was done under 
air pressure. Two iron-lined tunnels were run through this 
intersection first, and the side walls then built in. Openings 
were then made at the tops of the tunnels and timbering or 
sheathing was carried up so that sufficiently heavy false work 
could be put in for springing the arch. After the arch was 
completed the two temporary tunnels were taken out. This 
work required the greatest ingenuity and care, for at least eight 
weeks. Any accident to the timbering, any loss of the necessary 
air pressure or any carelessness of the men, would have undoubt- 
edly caused a cave-in; and the elevated structure and the 
surface lines, together with the streets and the buildings on 
each side, would have fallen into the excavation. Every square 

*J. Vipond Davies, in Railroad Age Gazette. 



166 SUBWAYS AND TUNNELS OF NEW YORK 

inch of the treacherous ground had to be protected by wooden 
sheathing the moment it was exposed; otherwise the vibration 
of the passing trains above would start the sand running. This 
part of the work was the last of the excavation necessary for 
opening the railroad to traffic, and although it was early in 
December when the spring of this large arch was under way, 
it was finished so that trains could be operated on February 10, 
1908.* 

It is interesting to note that the original Ingersoll air com- 
pressor installed at the Hoboken end of the first tunnel in 1880 
was continued in service until the completion of the tunnels. 
This compressor was overhauled in 1890 and is rated as an 
Ingersoll Class " A " with cylinders 20 inches and 20* inches 
by 30-inch stroke, free air capacity 1098 cubic feet per minute. 
The other compressors comprising the plants of the three power 
houses responsible for the tunnel work of the Hudson Com- 
panies all belong to the same family. Besides the compressor 
mentioned, the Hoboken plant included two Class " A " com- 
pressors, 22 and 26+ by 24-inch stroke, free air capacity 3686 
cubic feet per minute; and one duplex Class " H " Ingersoll- 
Rand machine, 16 and 2oJ by 16-inch stroke, free air capacity 
2178 cubic feet per minute. 

The Morton Street plant at the Manhattan end of the same 
tunnels comprised one duplex Ingersoll-Rand compressor, 
22 and 2 2j by 24-inch stroke, free air capacity 2640 cubic feet 
per minute; one Ingersoll-Rand Class " A " 22 and 22! by 24- 
inch, free air capacity 1320 cubic feet per minute; one 20 and 
22 J by 24-inch, free air capacity 1320 cubic feet per minute; 
and one 16 and 161 by 18-inch, free air capacity 698 cubic feet 
per minute. 

At the Jersey City plant opposite Cortlandt Street the 
machines were three Ingersoll-Rand Class " H '■ cross-com- 
pound steam, 2-stage air compressors for high pressure air, 
and three Ingersoll-Rand Class " H " cross-compound steam, 
duplex single-stage air for the low pressure air. The former 
were 14- and 28-inch steam and 24! and i4i-inch air, by 16-inch 

* From paper by Charles M. Jacobs. 



THE HUDSON-MANHATTAN TUNNELS 167 

stroke, free air capacity 4170 cubic feet per minute; and the 
latter of the same steam cylinder dimensions with air cylinders 
22 J by 16-inch stroke, free air capacity 7920 cubic feet per 
minute.* 

The Cameron sinking pump was used almost exclusively 
for taking care of the drainage water in the excavation of the 
Sixth Avenue subway. This pump is very light, compact and 
readily handled and was suspended on chains while in opera- 
tion. For its purpose as a sinking pump it is particularly 
well adapted to care for water carrying a large proportion of 
sand or sediment, as the water flows steadily in one direction, 
and is not retarded in its passage through the valves, which 
have large openings. These qualities permit of a comparatively 
high speed of the moving parts, and of a consequently large 
quantity of water discharged. 

The weight of the machine is reduced by discarding the 
valve chest and air chamber, as the valves are in the lower 
cylinder and plunger, and the upper part of the plunger performs 
the functions of an air chamber. The construction of the water 
end is very simple. All valves are readily accessible for inspec- 
tion, but as the flow of water is continuously in one direction, 
the accumulation of sediment or sand around the valves is pre- 
vented. This prevention of the obstruction of the water valves 
eliminates the most common cause of the pump troubles experi- 
enced in sinking pumps. 

* From Compressed Air Magazine. 



CHAPTER XXI 

THE HUDSON TERMINAL STATION OF THE HUDSON-MANHATTAN 

TUNNELS 

The provision for crossing the Hudson for the suburban 
population resident in New Jersey has heretofore been solely 
by ferry. This means of conveyance, requiring the transfer 
of passengers at each side of the river, is necessarily slow, due 
to the loading, starting, entering ferry slips and unloading, these 
delays being increased in case of fog or storm, or under winter 
conditions where the slips are jammed with ice. The ferries 
carry about 120,000,000 passengers per annum. 

Excepting the New York Central & Hudson River Railroad, 
and the New York, New Haven and Hartford, all the main 
railway lines terminate on the west bank of the Hudson and are 
cut off from direct connection with New York 

A tunnel connecting New York and the west shore was 
first practically considered in 1873, wnen the Hudson River 
Tunnel Company was organized, and laid plans for a line from 
a point at the foot of Fifteenth Street, Jersey City, under 
the Hudson to a point in Washington Square, New York 
City. This scheme was for a steam road with its terminal 
in Washington Square, the then resident district. The pro- 
nounced movement westward has necessitated the situation 
of the terminals in other sections. 

The center of greatest concentration in Manhattan is south 
of the City Hall, and in locating lines for a tunnel road the 
problem presented was: First, to locate close to Broadway 
and, second, to obtain a location where the cost of the site 
would not be prohibitive. It was undesirable to cross Broad- 
way, as the east side of that thoroughfare is of no greater value 
for handling passengers than the west side at an equal distance 

168 



THE HUDSON TERMINAL STATION 169 

from Broadway, while the cost and difficulties of caring for the 
old buildings and their foundations would have enormously 
increased the costs and hazards of tunnel building; and, in 
addition, the connections with other city lines are better west 
of Broadway. 

The scheme of operating the Jersey tunnels and the uptown 
lines fixed the train lengths at eight cars, each 48^ feet long, 
requiring a station track 388 feet long and platform lengths on 
a tangent of about 350 feet. 

The small area of land required for the underground terminal 
was very costly. The average price was, $40.00 to $45.00 per 
square foot, and in addition there were the payments under 
the franchise provisions for lease and use in perpetuity of the 
underground space of the adjacent streets. The original idea 
was to construct a railroad station with a simple shed cover 
over the area at the street level; but owing to the unremunera- 
tive conditions of this plan, the investment being about 
$3,000,000, it was decided to improve the property by the 
erection of an office building that would yield an income. 

The location adopted for the railroad was by a line from 
Jersey City eastward to the foot of Cortlandt Street, under 
Cortlandt Street to the private property at Church Street 
(the next street west of and parallel to Broadway) ; thence 
due north under this property and crossing under Dey Street 
to Fulton Street (420 feet between the north line of Cortlandt 
Street and south line of Fulton Street); thence turning west 
under Fulton Street and again crossing the Hudson River 
to Jersey City. The width of the station site averages 180 
feet, and, including the widths of Cortlandt and Fulton streets, 
the length north and south is 530 feet. 

The elevation of the tracks in the station was determined 
(subject to the limitations of the Rapid Transit Railroad Com- 
missioners) as 1 1.7 feet below mean sea level, or at a depth of 
36.86 feet below the street surface at Church and Dey streets; 
and this depth was altogether too great for the movements of 
passengers up and down without an intermediate landing. 
For railroad operation, the shorter the movement vertically 



170 SUBWAYS AND TUNNELS OF NEW YORK 

or horizontally between the concourse or distributing floor 
and the cars, the better; and as the clearance needed for the 
cars was only 12 feet 6 inches above top of rail, and the floor 
depth required was only 24 inches, a grand concourse was laid 
out at an elevation of 4.33 feet above mean sea level. In this 
case there was an added advantage, as at this level the concourse 
could be constructed continuous under Dey Street and prac- 
tically over the entire area of the station site. The only necessary 
function, therefore, of the street level in connection with the 
railroad station was to provide adequate access and egress for 
passengers, well distributed, to the concourse floor; and with 
that exception the^entire surface area was available as part of 
the office building now developed. 

The provision of platforms, stairways and openings had 
next to be considered. To do this intelligently it was necessary 
to work back from the ultimate carrying capacity of the tunnels. 
The capacity of each pair of tunnels is one trainload of 800 
persons on a headway of 90 seconds, or, say 530 persons per 
minute; and this number either arriving or leaving at times 
of maximum movement in one direction, as the reverse move- 
ment is always comparatively light. Two terminal station 
tracks will easily take care of this service, allowing three minutes 
for the train to enter and stand in the station. As there are two 
pairs of tunnels provided for the future (one pair of which is 
now in operation), the station was laid out with four operating 
tracks, and an additional track, allowing only for unloading 
passengers, for car inspection and for storing disabled trains. 
The unloading platform widths and areas need to be sufficient 
to hold only such part of the trainload as would not have passed 
onto the stairs when the last portion of the train load has dis- 
charged; and obviously a floor area equal to the train itself 
is more than adequate providing there is no undue congestion 
on the stairs. In order to load a train promptly the loading 
platforms should have sufficient area for a trainload of passengers 
to stand without undue crowding, largely grouped along the 
edges at the points where the car doors come when the train 
stops, with sufficient space in addition to permit a free passage 



THE HUDSON TERMINAL STATION 171 

through the crowd being maintained. The width should be 
greater than that of the unloading platforms and should not 
be less than twice the width of the trains. Alternating the 
platforms as before mentioned and thereby maintaining one- 
way movement, permits this. The platforms as finally arranged 
are as follows: 

Along the Church Street side, an unloading platform ni 
feet wide serving one track; area 5200 square feet. 

Between tracks Nos. 1 and 2, a double loading platform 
22 feet wide; area 9000 square feet. 

Between tracks Nos. 2 and 3, a double unloading platform 
22 feet wide serving two tracks; area 9300 square feet. 

Between tracks Nos. 3 and 4, a double loading platform 
22 feet wide serving two tracks; area 9300 square feet. 

Between tracks Nos. 4 and 5, a single unloading platform, 
13 feet wide, serving No. 5 track only in emergency and being 
regular only for No. 4 track; area 5400 square feet. 

To ascertain the necessities in respect of stairs and passages, 
count of actual movement of traffic at congested points in New 
York was made, notably at the Brooklyn Bridge. In a straight 
passage of ample width, the " rush hour " New York crowd moves 
at a rate of 300 feet per minute, walking with a step averaging 
30 inches. There is only a small reduction in this speed on 
ramps of, say, not over 10 per cent grade. At this rate each 
person averages about 10 square feet of space occupied and the 
movement discharges about 30 persons per foot of width of pas- 
sage. If the passageway becomes too congested, the space 
occupied per person reduces and the speed of movement also 
reduces, but the number discharged remains about the same, 
thirty per minute. Any contrary movement in a broad passage 
reduces the movement rather more than the relative space 
occupied in multiples of, say, 30 inches per person; but in 
narrow passages the relative reduction is much greater, not- 
withstanding that persons crowd into smaller space, not over 
24 inches in width. 

A crowd moving freely upward on stairs takes about the 
same number of steps per minute, say 120, but advances only 



CORTLANDT STREET 




FULTON STREET 

Foundation and Track Arrangement, Hudson Terminal Station. 



172 SUBWAYS AND TUNNELS OF NEW YORK 

about 12 inches horizontally instead of 30 inches. Upstairs 
movement is much more dense than downstairs, but correspond- 
ingly slower. We have counted discharge on stairs of 24 persons 
per foot of width per minute moving upward, but never more 
than 18 per foot of width moving downward. There does 
not appear much difference in discharging rate on stairs above 
4 feet wide if the movement is all in one direction; but stairs 
of all widths (particularly below 8 feet wide) are seriously 
impeded by any contrary movement even when only four or 
five persons per minute are moving in the direction reverse to 
the heavy traffic. Generally, for stairs above 4 feet in width, 
all movement in one direction, actual count indicates: 

Upward — Maximum, 20 persons per foot of width of stairs 
per minute. Average for ordinarily free-moving crowds, 15 per 
minute. 

Downward — Maximum, 18 persons per foot of width of 
stairs per minute. Average for ordinarily free-moving crowds, 
13 per minute. 

In case of any contrary movement it is most important 
to force the people to a right-hand direction of movement, and 
speaking generally no stairs serving traffic in contrary directions 
for railroad service should be permitted to be installed of less 
than 5 feet clear width. 

In unloading railroad trains in rapid transit service, it is 
very important to distribute passengers as quickly as possible, 
particularly in discharge; and, in such a problem as ours, to 
get them off the track platforms as rapidly as possible and 
with the least amount of walking along the platforms, allowing 
them the more easily to freely distrubute themselves on the 
great concourse floor. In a full train there are, say, twenty 
door openings in the train, all simultaneously discharging 
practically a single line of persons. Therefore, we located 
stairways on all the unloading platforms in tandem, six stairs 
to each, distributed as nearly uniformly along the platform 
lengths as possible. No. 1 platform has an aggregate of 26- 
foot stairs to discharge at the rate of 800 persons in a 3-minute 
interval, or 266 persons per minute, or say, 10 persons per foot 



THE HUDSON TERMINAL STATION 173 

of width of stairs. No. 3 platform has six stairs (one not fitted 
until needed) aggregating 48 V feet in width for discharge of 
800 persons in 90 seconds, or say 9 persons per foot of width 
per minute. 

For the loading platforms, it was important for the economical 
operation of the railroad to group the landings on the concourse 
floor, and consequently it was necessary to provide for this 
service only four stairs per platform in pairs. These have an 
aggregate width of 32^ feet, and a maximum passenger movement 
of 16 persons per foot of width per minute, on the assumption 
that the train is fully loaded at the terminal station and no con- 
sideration given to local movement at other stations. 

The arrangement of stairway heads on the concourse floor 
tends as far as it is possible to thoroughly distribute the move- 
ment, and also to separate the incoming from the outgoing 
traffic. The distribution of the streams of traffic cannot be too 
thoroughly separated to obtain the best results. At the same 
time, having in mind that when the movement eastward is at 
its maximum and carrying 7.5 per cent of the total daily traffic 
between 7 a.m. and 8 a.m., the westward movement is only 
1.5 per cent of the total daily traffic; and in reverse direction 
when between 5 p.m. and 6 p.m. the maximum westbound 
traffic represents 10.7 per cent of the total daily traffic, the 
eastbound traffic only represents 2.5 per cent of the total daily 
movement. 

The original plan designed was to absolutely separate the 
movement on the street by making two main entrances on Dey 
Street near Church Street, each 30 feet wide, the entire entrance 
for all the traffic descending by arcade passages and easy stairs 
to the concourse; and one main exit each at Cortlandt Street 
and at Fulton Street, each 30 feet in width, and ascending by 
arcades and easy ramp sloping from 10 to 14 per cent from the 
concourse. As, however, the aggregate of these main entrances 
provided for less than 9 persons per foot of width per minute 
and the office buildings were greatly benefitted by making all 
these main approaches equally entrances and exits, the first 
plan was modified to that extent and the freedom of movement 



174 SUBWAYS AND TUNNELS OF NEW YORK 

is much better adapted to the general approach through the 
streets to the station and reduces thereby the general congestion 
on the streets. 

The first essential purpose of this railroad and station is 
for the operation of a purely local rapid transit passenger ser- 
vice, but, as before stated, the railroad was also to operate a 
terminal service for the various steam railroads in Jersey City 
and Hoboken. It was, therefore, also necessary to equip the con- 
course floor with ticket offices for these various trunk line rail- 
roads, enabling them to sell all classes of tickets for all points 
on their systems for trains departing, and to advertise schedules 
of trains departing, from Church Street terminal. A train 
leaving at an advertised time becomes the train connection 
for the specified steam railroad train from New Jersey. The 
ticket examiners at the ticket barriers on the concourse floor 
announce the train connection and at the leaving time of the 
train deliver a clearance ticket for the train to the conductor, 
who in turn surrenders the clearance ticket to the platform 
man at the respective stations on the New Jersey side, on 
receipt of which ticket the main line train is despatched. 

The construction and design of this combined station and 
office building need a very brief description. The structure 
below the surface is the greatest example of caisson construc- 
tion in existence. The soil underlying the site was quicksand 
down to the level of the hardpan, which was an irregular deposit 
overlying the bedrock (New York micaceous gneiss). All sur- 
rounding buildings were on old and inadequate foundations, 
and the plans for the electrical power plant to be put in below 
the track level required excavation to a depth of 75.8 feet below 
Church Street, or 50.7 feet below tide level. In addition to the 
building with its foundations, the approaches for the tunnels 
to the station at either end had also to be constructed by sinking 
caissons under the streets and from building line to building 
line without interfering with the use of the streets during con- 
struction. The main station site was first enclosed by sinking 
51 rectangular caissons, joined to each other, around the 
external lines. All these caissons are of reinforced concrete, 8 



THE HUDSON TERMINAL STATION 175 

feet thickness of wall, and all caissons were sunk through hard- 
pan to bedrock and sealed into the rock. Rock at its deepest 
point is iio feet below the surface of Church Street. Inside 
the area of the enclosed coffer-dam were then sunk 115 circular 
pits and 32 rectangular pits, in caissons down to hardpan, these 
pits corresponding to each column location; and in these pits 
were constructed the grillages and foundations for columns. 
Up to this point excavation had only been carried down to about 
the concourse floor level where water stood in the ground. The 
steel columns for the triple tier from foundation to street floor 
level were then erected in these pits ; the lower length of column 
weighing as much as 26 tons each and carrying loading up to 
1725 tons per column. The columns being erected, the steel 
of the concourse floor was then erected and the floor filled with 
solid Portland cement concrete from wall to, wall. Excavation 
was then carried down to the train deck. From that floor the 
main girders on rectangular system between columns were 48 
inches deep, flanges 16 inches wide. The floor had to carry the 
train loading as well as to be the main strut to carry the external 
pressures on the external walls. It was, therefore, determined 
to construct this of excessive mass and strength by putting 
in a solid slab, 36 inches thick, of reinforced Portland cement 
concrete, burying columns and girders in one continuous mass. 
The enormous external pressure may be appreciated from the 
fact that during excavation from the concourse to the train 
floor and while waiting for steel girders to be delivered, the 
entire wall along Church Street bowed in 10 inches without 
crack or apparent injury. 

After the track floor construction was complete, excava- 
tion was carried down to the bottom. The bottom of the rail- 
road's transformer sub-station No. 3 was excavated down 
to bedrock. The entire balance of area of basement had all 
quicksand removed to hardpan or rock and the area backfilled 
with boiler cinders and thoroughly sub-drained to the sump 
where automatic ejectors are installed. Since construction, 
it is found that the entire drainage through the walls and into 
the foundations is insignificant and negligible. To construct 



176 SUBWAYS AND TUNNELS OF NEW YORK 

this basement it was necessary to build the coffer-dam continuous 
but at the same time the approaches under Cortlandt Street 
and Fulton Street were also being sunk in caissons connected 
end to end with removable steel end walls used only for sink- 
ing purposes; and these approaches involved 33 caissons having a 
total cubic capacity of 25,000 cubic yards. These being sunk 
to final grade, sealed, roofed, and in every way made secure, 
the trainways through the main coffer-dam walls were blasted 
out. This was a most difficult job, executed while the office 
buildings were fully occupied. The trainways represented 120 
feet of regular railroad tunnel. The total quantities involved 
in work below the street level, as illustrating the magnitude of 
the undertaking, were as follows: 

238,000 cubic yards excavation 
80,000 cubic yards excavation in caissons 
1 1 ,000 cubic yards concrete in caissons 
6,267 tons structural steel 

In the basement of the buildings is the following equipment : 

Electric transformer sub-station transforming current gen- 
erated in Jersey City power house, transmitted at 11,000 volts 
a.c. to current at 625 volts d.c. for railroad operation and 240 
volts d.c. for the power and lighting of the buildings. 

A complete school of instruction for railroad employees, 
fitted with a full-sized car and signal equipment. 

Club, reading and dressing rooms for employees. 

Suction and forced draft fans for tunnel ventilation, and 
also similar machinery for ventilation of the basement and 
the buildings. 

Absorption ice-making plant (Carbondale type) for clubs, 
restaurants and markets. 

1500 h.p. boiler plant (Babcock & Wilcox). 

Isolated generating plant for supplying entire buildings. 

Storage battery plant. 

Hydraulic pumps for all baggage elevators. 

Extensive baggage rooms and space for handling and storage 
of baggage or freight. 



THE HUDSON TERMINAL STATION 177 

Coal bunkers, capacity 1500 tons, constructed of reinforced 
concrete. 

In addition to the local passenger business of the Hudson- 
Manhattan Railroad, it is obvious from the foregoing descrip- 
tions that the railroad is also laid out to be the distributing 
terminal for the steam trunk lines terminating in New Jersey. 
This is anticipated in the fact that the company is now con- 
structing a physical connection to the tracks of the Pennsylvania 
Railroad so that its electric trains can be run over the tracks 
of the Pennsylvania Railroad from the suburban district in 
New Jersey into the tunnels of the Hudson and Manhattan 
Railroad, either to the Church Street terminal or ultimately 
uptown to Forty-second Street, Grand Central Station. Further 
than this, a connection is anticipated from the Erie direct to 
the Church Street terminal. 

For handling baggage there are four elevators of the Otis 
plunger type, the floor area of each averaging 12 by 6 feet. 
These elevators are equipped with rams 9+ to 12? inches in 
diameter and have a lift of 23 feet; capacity of the elevators 
is 8000 to 13,000 pounds. One of these elevators is installed 
at each end of each of the loading platforms, and the main Dey 
Street baggage elevators serve the No. 6 platform by a door 
opening onto that platform direct. The means is, therefore, 
provided for getting baggage onto each or any one of the plat- 
forms serving the five separate tracks at either end. 

The development and use for railroad purposes of the space 
below street level only, allowed of the full treatment above the 
surface of almost the entire area. This very great area per- 
mitted the design of office buildings on strictly economical 
lines which would be noteworthy and handsome if for no other 
reason than on account of their enormous mass and simplicity. 

There are two of these buildings 22 stories in height above 
the street, the combined cubical contents of which are approxi- 
mately 15,000,000 cubic feet. Both of these superstructures 
were so designed as to have easy access from the elevator halls 
to the concourse floor below. 

The Sixth Avenue elevated station at Cortlandt Street 



178 SUBWAYS AND TUNNELS OF NEW YORK 

connects with the corridors on the third floor of the building 
on Cortlandt Street and the twin buildings are connected by a 
bridge on this floor crossing Dey Street. 

There are 39 high-speed i-to-i traction elevators, 22 of which 
are express elevators running to the twenty-second floor, and 17 
local elevators running to the eleventh floor. Three of the ele- 
vators run down to the concourse floor, but are not at present 
used except in cases of emergency. 

The rental area of the buildings is approximately 815,000 
square feet, exclusive of the valuable rental space on the entire 
concourse floor. 

In order to construct these buildings enormous quantities 
of materials were required; there are approximately 17,000,000 
bricks above the surface of the ground, and in the sub- 
structure and super-structure combined there are 27,000 tons 
of steel. 

There are four entrances to the railroad station, or concourse 
floor. The approaches on Cortlandt and Fulton Streets are 
by means of ramps and the two on Dey Street by means of 
stairways. These approaches are very simple in design and 
are arranged with shop windows all around. At the ends of 
these approaches are four large clock panels designed by Mr. 
Carl Bitter. Steel and glass marquises cover the entire width 
of the sidewalk over all entrances. The floors of the ramps 
are of cement mixed with carborundum so as to avoid slipping. 
The stairways are of blues tone. 

All renting spaces are designed on a strictly commercial 
basis and the entire station, including the concourse floor and 
the railroad platforms, are built so as to be as sanitary as pos- 
sible. The floor of the concourse is of white terrazza with colored 
mosaic bands, and all walls and columns have a white glazed 
terra cotta wainscoting with sanitary base and decorative cap 
of the same material. The walls above the wainscoting are 
of hard plaster; all angles are coved or round, and the entire 
plaster work is painted with enamel paint. 

On the concourse floor every convenience of the modern 
terminal station is provided for the public and every effort has 



THE HUDSON TERMINAL STATION 179 

been made to make it attractive. This floor is approximately 
430 feet long by 185 feet wide, and of this space aisles which 
approximate a total of 100, feet in width are given up to the 
public, with ticket booths arranged at convenient points, giving 
an unobstructed view of the whole length of the floor. On this 
floor, in addition to the ticket ofnces of the Hudson and Man- 
hattan Railroad Company, are the ticket ofnces of the Penn- 
sylvania, Erie and Lehigh Valley Railroads. There are ample 
waiting rooms with first-class toilet accommodations; and bag- 
gage and parcel rooms, barber shops, bootblacks, telephone 
and telegraph booths, and shops at which nearly everything 
that the commuter requires may be purchased. 

This combination of a railroad terminal and an office build- 
ing above, presented problems which would not arise in the 
case of either proposition if handled by itself. The most serious 
of these is the arrangement of the columns so that as far as 
possible they would allow of a proper architectural treatment 
of the buildings and still maintain the right-of-way of the tracks 
in the sub-structure, This was accomplished in the main 
body of the plot, but at the Cortlandt and Fulton Street ends 
where the tracks converge to run down the streets, it was found 
necessary to have the building columns rest on girders, which 
were carried by columns extending through the track floor, 
which columns were located so as to leave proper clearance 
for the tracks. The distributing girders were placed at the 
concourse floor level and are made up of three single girders, 
each 72 inches deep, with a flange width of 10 inches; and as 
these girders when set up were very wide, and it being almost 
impossible to design proper caps for the columns which supported 
them, mill slabs of steel were used; these were in some cases 
6 inches thick. 

Another point which had to be taken care of was the multitude 
of pipes and wires which were necessary to connect the build- 
ings above the track and concourse floors with the power and 
heating plants which were located below these floors, partic- 
ularly bearing in mind that the passage through the track floor 
must not by any connections obstruct more than necessary the 



180 SUBWAYS AND TUNNELS OF NEW YORK 

space occupied by platforms. This was accomplished by con- 
necting up groups of pipes or wires into systems of piping 
which for convenience were termed sub-mains, which sub-mains 
were in turn connected to the mains in the basement by means 
of large vertical risers termed sub-main feeders. By this means 
the amount of room required for piping and wire shafts was 
reduced to a minimum; and as these are usually placed near 
columns, the size of the finish around columns was reduced 
quite materially and thereby unnecessary obtruction of the 
track platforms was avoided. 

These sub-mains were placed near the concourse ceiling 
and to make proper finish for the concourse a hung ceiling was 
erected under same with trap doors for easy access to the con- 
trol valves. 

The entire lighting of the buildings and sub-structure is 
by means of high efficiency lamps and specially designed 
fixtures*. 

The location of these twin buildings in conjunction with 
the railroad station terminal has created a new center of popula- 
tion where previously only a small .community was gathered. 
The present aggregation of persons transacting their daily 
work under these roofs is 8000 and with the complete rental 
of all space will amount to approximately 10,000. 

The property was purchased in the early part of 1906 and 
some few buildings standing thereon were razed at that time. 
It was not, however, until May 1, 1906, that the bulk of the 
properties was turned over to the railroad company. The 
company by its own engineers carried out all work of construc- 
tion of the railroad station, approaches, foundations and sub- 
structure below street level. The caisson and foundation work 
had advanced so that on May 12, 1907, the first grillage and 
column were set in the permanent structure, and on April 4, 
1908, the company moved into its offices in the completed build- 
ing. The completion of tunnel approaches, tunnels and ter- 
minal station, however, took considerably longer, the railroad 
going into operation July 19, 1909. 

The design and construction of tunnels, station and sub- 



THE HUDSON TERMINAL STATION 181 

structure were by Jacobs & Davies, engineers of the company, 
while the entire design of the buildings, and treatment and 
decoration of the station were by Clinton & Russel, architects. 
George A. Fuller Company was the contractor for the buildings. 

From a paper before American Institute of Architects by J. Vipond Davies 
and J. Hallis Wells. 



APPENDICES 



APPENDICES 

A. Air Compressors in the New York Tunnel Work. 

B. The Compressed Air Plenum. 

C. The Use of Compressed Air in Tunneling. 

D. Special Types of Air Compressors. 

E. Straight Line and Duplex Compound Air Compressors. 

F. Compound Air Compression; Altitude Compression; Air 

Cylinder Lubrication. 

G. Some Air Lift Data. 

H. Compressed Air Locomotives. 

I. Rock Drills; Hammer Drills. 

J. x Tunnel Carriage for Drilling; Electric- Air Drill. 

K. Rock Drill Bits; Drill Sharpening. 

L. Selection of Explosives; Dampness and Dynamite; Blasting 

Gelatine; Cost of Blasting in Open Cuts. 
M. Pumps for Sinking and Tunneling; Sinking Caissons. 
N. Engineering Data. 



184 



APPENDIX A 

Air Compressors on New York Tunnel Work 

The tunnel stage of the development of New York City 
may be said to have really commenced with the present century. 
Although the first tunnel under the North River was planned 
and begun a quarter of a century ago, it has but recently been 
completed, with also its twin tunnel for the reciprocal traffic. 
On account of the earlier completion of connections, other 
tunnels begun within the present century will be in established 
service before these. 

The tunnels completed or approaching completion, includ- 
ing the two mentioned above, are as follows: 

Six tunnels under the North River; the two from Morton 
Street, Manhattan, to Hoboken to be used for local and sub- 
urban electric train service; two near Cortlandt Street for the 
same system; two at about Thirty- third Street for the Penn- 
sylvania Railroad. Eight under the East River; two from the 
Battery up into the heart of Brooklyn, as a continuation of the 
already completed subway; four to connect the Pennsylvania 
Railroad with the Long Island Railroad, two of these tunnels 
also extending across Manhattan; and the two so-called Bel- 
mont tunnels which are to connect the Forty-second Street line 
of the present subway with Long Island trolley lines. 

This tunnel work involves not only the actual driving of 
the tunnels under the rivers as indicated, but greater additional 
lengths of subterranean tunneling for the approaches or con- 
nections. Other tunnels " too numerous to mention " in these 
and other directions are planned and more or less specifically 
provided for to supply work for at least twenty years ahead, 
by which time the tunnel habit will have become so established 

185 



186 SUBWAYS AND TUNNELS OF NEW YORK 

that no one now can suggest the amount of subterranean and 
subaqueous excavation and construction which will ultimately 
be required in New York and vicinity. 

We have here to do with only one, although the most import- 
ant, physical agency in all this tunnel work, the compressed 
air supply. Merely to enumerate the air compressing plants 
which have been installed in New York for tunnel work alone, 
with mention of a few of their most important details, is enough 
for the present paper. 

It will be noted that all the air compressors herein enu- 
merated are New York machines, machines largely developed 
by New York practice in the building of the Aqueduct, supple- 
mented by mine and tunnel work throughout the world; and 
perfected and manufactured by the two New York companies 
of world-wide reputation in this line, the Ingersoll-Sergeant 
and the Rand, now in the natural course of business events 
combined in a single concern, the Ingersoll-Rand Company. 
The position of this company in this great metropolitan develop- 
ment is unique, and cannot be approached for parallel or com- 
parison in any other line of business. 

That there is plenty of tunnel work ahead for the air com- 
pressor might well be inferred from the substantial and appar- 
ently permanent character of many of the installations. Sev- 
eral of the plants here mentioned will undoubtedly be employed 
to supply the air for other tunnels besides those for which they 
have been originally erected. These plants accordingly have 
generally nothing cheap or temporary about them. They 
employ all the usual well-known devices of economy both in 
the use of steam and in the compression of the air. The boilers 
are all of modern design and nearly all of the water- tube type. 
The steam units are usually compound and condensing, and the 
air compression two stage with intercoolers and aftercoolers. 
Gravity oiling systems are installed, which constantly and 
perfectly lubricate every part and return the oil for repeated 
use. The action of the compressors is regulated automatically 
according to the call for the air, so that a series of machines will 
run constantly without handling the throttle. Recording gages 



APPENDIX A 187 

are generally employed and their records are watched and filed 
in the offices. 

While as a rule nothing has been neglected in the installa- 
tion of these plants which could contribute to the reliability 
and economy of their operation, to the accessibility of parts 
and to convenience of manipulation, so that, seen within and 
with all the circumstances considered, many of them may be 
taken as models of their class, but the slightest thought has 
been given to the exteriors of the buildings. One plant is located 
in an old church, another in a dilapidated foundry, and in 
several cases the compressors, boilers, etc., have been com- 
pletely placed in the open air and their protective sheds or 
buildings have been erected over them. 

The perfection and endurance of the compressors may be 
noted as remarkable. The writer hereof more than a year ago 
personally visited every plant mentioned except that upon 
Man-O'-War's Reef, the improvised island in the East River; 
and while most of the compressors seen were being worked to 
the limits of their capacity, running at speeds which were aston- 
ishing, not one was seen out of order or undergoing repairs. 
The arduous work on the New York Aqueduct and in tunnels 
and mines everywhere has to a remarkable extent revealed and 
eliminated the weak spots and suggested successive improve- 
ments. 

As indicating the speeds at which these compressors may 
be run, it may be specially noted that five duplex Corliss com- 
pressors, 42-inch stroke, in the Manhattan plant of S. Pearson 
& Son, Inc., were designed and guaranteed to run continuously 
at 100 r.p.m., or 700 feet piston speed, with a further provision 
that in case of emergency they would be capable of running at 
125 r.p.m. for a period not exceeding twenty-four hours. This 
emergency has been encountered several times since the plant 
was installed, and in fact the machines have run as high as 135 
r.p.m. or 945 feet piston speed, for long periods without appar- 
ent distress. 

In the estimated free air capacities given herein for each 
plant the piston speed assumed for all is 500 feet per minute. 



188 SUBWAYS AND TUNNELS OF NEW YORK 

The one-quarter inch additional to the nominal diameters of 
the Ingersoll air cylinders is dropped out of the computations, 
as this normally compensates for the area of the piston inlet 
pipe, although in some of the compressors with mechanically 
operated valves this pipe is not used. 

Pennsylvania Station Excavation. The work of excavating 
for the New York terminal of the Pennsylvania Railroad is 
not at all tunnel work, but it is at the point where four of the 
tunnels are to meet. This work was, to think of, a simple affair. 
It was only to dig a hole in the ground; but it was a hole 
measuring roughly, in the main portion of it, 1800 by 400 feet 
and 40 feet deep, with more than 1,500,000 cubic yards of 
material to be removed. A considerable portion of the top was 
sand and gravel, which was removed first, but most of the 
material is solid rock. Both steam and compressed air are 
employed on the work. The steam shovels, being self-contained, 
also some traveling derricks and of course all the locomotives, 
are steam operated; while rock drills, pumps, many hoists, 
concrete mixers, etc., are driven by compressed air; and 
here, as elsewhere, the compressors are driven to their full 
capacity. 

A temporary compressor plant was first installed right 
upon a portion of the ground to be excavated, the exterior of 
the plant being shown in Fig. 1. The church and appurtenances 
in the background have since been pulled down and rock cutting 
is proceeding upon the site. There were here three Rand 
straight line Class " C " compressors with cylinders 24- and 
26-inch diameter by 30-inch stroke, free air capacity 5529 
cubic feet per minute; and one Ingersoll Class "A" piston 
inlet compressor 24- and 2 6 \- by 30-inch stroke, free air capacity 
1843 cubic feet per minute. The steam cylinders had balanced 
valves and Meyer adjustable cut-offs and worked non-con- 
densing. The steam pressure carried was no pounds and the 
air pressure 90 pounds, the latter not being always maintained, 
as the air was used as fast as it could be delivered. The rock 
drilling, however, was kept constantly in advance of the work 
of removal and many holes were always waiting to be fired 



APPENDIX A 



189 



when needed. The air was not cooled except by the water 
jacket. There were two large air receivers and a combined 
delivery pipe 8 inches in diameter with valves for disconnecting 
each compressor. The air line was carried around the excava- 
tion with distributing branches where required. There were 
six locomotive boilers burning small anthracite. A Cochrane 
feed water heater was in service and two duplex steam pumps 
for boiler feeding. 

It was well to mention this plant first, since it was, with 
perhaps one exception, the least economical of any of the plants 




Fig. 1. — Temporary Power House, Pennsylvania Terminal. 



here enumerated. Fig. 2 shows the exterior and Fig. 3 the 
interior of the more permanent installation of the New York 
Contracting Company for this Pennsylvania terminal excava- 
tion. This is a plant of much larger capacity and does its 
work much cheaper. The building, as is evident, was a church, 
but the interior is now as unecclesiastical as could well be 
imagined. 

There are here three 2 -stage, electrically driven Rand 
compressors with air cylinders 30- and 19-inch diameter by 30- 
inch stroke; free air capacity 8983 cubic feet per minute. The 
induction motors are each 500 h.p. General Electric, type L.M., 



190 



SUBWAYS AND TUNNELS OF NEW YORK 



122 r.p.m., 6600 volts, 3 -phase, 25-cycle. There is also one 
Rand Corliss, cross-compound, girder frame, 2-stage compressor 
with steam cylinders 22- and 40-inch and air cylinders 38- and 
23-inch by 48-inch stroke; free air capacity 3937 cubic feet 
per minute. In addition to these are the four compressors of 




^ i I 



Fig. 2. — Exterior of Power House, Pennsylvania Terminal Excavation 

the temporary plant previously enumerated and therefore 
not mentioned further and not repeated in our final sum- 
mary of the various plants. 

Pennsylvania Railroad East River Tunnels, Manhattan Plant. 
The plant of the contractors, S. Pearson & Son, Inc., at Thirty- 
third Street and First Avenue, New York, is in marked contrast 



APPENDIX A 



191 



to the preceding. Fig. 4 is a snap-shot of the exterior and Fig. 
5 shows the interior. The entire equipment in this case was 
installed under the direction of the builders of the compressors, 
the Ingersoll-Rand Company. There are four cross-compound 
Corliss compressors with steam cylinders 16- and 34- by 42-inch 
stroke, and duplex air cylinders 26J-inch, for a maximum air 
pressure of 50 pounds; free air capacity, 14,744 cubic feet per 
minute. There is another cross-compound Corliss compressor 




Fig. 3. — Interior of Power House for P.R.R. Terminal Excavation. 



of the same stroke and with the same steam cylinder dimensions 
as the above, but with duplex air cylinders i5|-inch diameter 
designed to compress to 140 pounds air pressure. The air for 
this compressor may be taken into the cylinders at the atmos- 
pheric pressure, or it may be taken in at 40 or 50 pounds pres- 
sure from the aftercooler of the low pressure service, thus increas- 
ing its delivery at the high pressure about fourfold; free air 
capacity, 13 10 cubic feet per minute. Another compressor 
has a special combination feature. It is a cross-compound 



192 



SUBWAYS AND TUNNELS OF NEW YORK 



Corliss compressor with the same steam cylinder dimensions 
as above, but with tandem air cylinders 23^ and 15! inches in 
diameter on each side. All the air cylinders may be used to 
compress atmospheric air to 50 pounds pressure and deliver 
individually into the low pressure service; or, by disconnect- 
ing the 23J-inch cylinders, the smaller cylinders may be used 
for the high pressure service, 140 pounds, precisely the same 
as the preceding machine. Free air capacity of this com- 
pressor is 4194 cubic feet per minute. Besides these, there 
are two straight line Class "A" compressors 18- and i8f- 




Fig. 4. — Manhattan Power House for P.R.R. East River Tunnels. 



by 24-inch stroke used for preliminary development work 
and generally held in reserve; free air capacity, 1766 cubic 
feet per minute. This is the plant mentioned above, guaran- 
teed to work up to a piston speed of 700 and in emergencies 
to 875 feet per minute, and which has been run up to 945 
feet in actual work. 

There are here six 500 h.p. Sterling boilers, three Wheeler 
condensers, with independent Edwards air pumps, three cen- 
trifugal pumps of the Buffalo Forge Company supplying water 
from the East River for jackets, intercoolers, aftercoolers and 
condensers, duplex boiler feed pumps in duplicate, a separate 



APPENDIX A 



193 




194 



SUBWAYS AND TUNNELS OF NEW YORK 



system of gravity lubrication, a special loop steam system 
with Holly drip arrangement, and a chemical oil separator. A 
working steam pressure of 150 pounds is carried throughout 
and everything possible is run condensing except what is required 
for heating the feed water. The power house contains three 
high speed engines with direct-connected generators and three 
duplex high pressure hydraulic pumps automatically controlled 
to supply water for advancing the shields, with which we here 
have nothing to do. Total free air capacity of plant is 22,014 
cubic feet per minute. 




Fig. 6. — Long Island City Power House for P.R.R. East River Tunnels. 



Pennsylvania Railroad East River Tunnels, Long Island City 
Plant. This plant of S. Pearson & Son, Inc., at Flushing 
Street and East River has the same units as the above, except 
that it has no Class "A" compressors, and the entire plant is 
quite differently arranged, the large yard space allowing great 
length for the power house. Fig. 6 is a snap-shot of the 
exterior. The vertical pipes which will be noticed, capped with 
strainers, are for the intake air. Instead of the Class " A " 
compressors an additional Corliss compressor, the same as the 
others for low pressure air, was installed, making the total 



APPENDIX A 195 

free air capacity of the plant at 500 feet piston speed 23,934 
cubic feet per minute. 

Pennsylvania Railroad North River Tunnels, Manhattan 
Plant. The plant of the O'Rourke Engineering Construction 
Company at Thirty-third Street and Eleventh Avenue, New- 
York City, the general exterior of which is shown in Fig. 
7, comprises three Ingersoll-Rand Corliss compressors with 
steam cylinders 14- and 30- by 36-inch stroke and duplex air 
cylinders 231-inch diameter, for maximum air pressure of 50 
pounds; free air capacity, 8652 cubic feet per minute. There 



Fig. 7. — Manhattan Power House for P.R.R. North River Tunnels. 

is also one cross-compound Corliss compressor with steam 
cylinders 14- and 22- by 36-inch stroke and duplex air cylinders 
i4i-inch diameter to compress to 140 pounds, using either 
free air or air taken from the af tercoolers of the low pressure 
compressors. Free air capacity is 1068 cubic feet per minute. 
Pennsylvania Railroad North River Tunnels, Weehawken 
Plant. This plant, also of the O'Rourke Engineering Construc- 
tion Company, foot of Baldwin Avenue and North River, 
Weehawken, N. J., is an exact duplicate of the preceding. Total 
free air capacity is 9720 cubic feet per minute. The interior 
of this plant is seen in Fig. 8. 



196 



SUBWAYS AND TUNNELS OF NEW YORK 



Pennsylvania Railroad Tunnel Under Bergen Hill. This 
plant of the John Shield's Construction Company at Hemp- 
stead., N. J., comprises one Ingersoll Class " A " compressor, 
24- and 24^- by 30-inch, free air capacity 1570 cubic feet per 
minute; and four Rand Class " C " 24- and 24- by 30-inch ; free 
air capacity, 6280 cubic feet per minute. 




Fig. 8. — Interior of Weehawken Power House for P.R.R. 
North River Tunnels. 



New York and Brooklyn Subway Tunnel, Battery Park, 
Manhattan. The principal compressor in this plant of the 
New York Tunnel Company, the contractors, is an Ingersoll- 
Rand cross-compound Corliss, steam cylinders 24- and 44-inch 
diameter and 48-inch stroke, with 2-stage piston inlet air 
cylinders 36J- and 22|-inch diameter. The engine has its own 
air pump and condenser; free air capacity, 3534 cubic feet per 
minute. This compressor was originally installed at Jerome 
Park Reservoir, where it was in service about six years. 



APPENDIX A 197 

Besides this, there are two Ingersoll Class "A " compressors, 
24- and 24 J- by 30-inch stroke, free air capacity 3140 cubic 
feet per minute. There are two Heine and two Hogan water 
tube boilers. 

New York and Brooklyn Subway Tunnel, Joralemon and 
Forman Streets, Brooklyn. This plant, while of considerably 
larger total capacity than that at Battery Park, has for its 
largest unit the other Jerome Park Reservoir compressor, an 
Ingersoll cross-compound Corliss with steam cylinders 24- and 
44-inch diameter by 48-inch stroke and single stage, piston 
inlet air cylinders 24|-inch diameter. Free air capacity is 3140 
cubic feet per minute. This compressor also has its own air 
pump and condenser. There are also two Ingersoll cross-com- 
pound Class " GC " compressors with steam cylinders 22- and 
34-inch diameter by 24-inch stroke and single stage piston 
inlet air cylinders 30^ and 285-inch diameter. The difference 
in the diameters of these cylinders is due to the exigencies of 
manufacture when the machines were required at very short 
notice. These compressors were not required to compress the 
air to above 25 or 30 pounds; free air capacity, 9184 cubic feet 
per minute. 

There is one Rand Class " B-4 " cross-compound compressor 
with single stage air cylinders, steam cylinders 20- and 32-inch 
diameter by 30-inch stroke and air cylinders 26-inch diameter, 
free air capacity, 3686 cubic feet per minute; and two Inger- 
soll Class " A " straight line piston inlet compressors, 24-inch 
steam and 24f-inch air by 30-inch stroke, free air capacity, 
3140 cubic feet per minute. 

Belmont East River Tunnel Plants. As these were the subject 
of a previous article (see Chapter XVIII) we here merely enume- 
rate the sizes and capacities of the compressors employed. At 
Forty-second Street, Manhattan, there is in one power house a 
Rand cross-compound Corliss 2-stage air compressor with steam 
cylinders 24- and 40- by 48-inch stroke and air cylinders 39- 
and 24-inch; free air capacity, 4147 cubic feet per minute; 
and an Ingersoll cross-compound Corliss 2-stage compressor 
with steam cylinders 22- and 40- by 42-inch stroke, and air 



198 



SUBWAYS AND TUNNELS OF NEW YORK 



cylinders 38- and 24-inch; free air capacity, 3937 cubic feet 
per minute. In the other power house there are three Inger- 
soll cross-compound steam, duplex air Class " H " compress- 
ors with steam cylinders 15- and 28- by 16-inch stroke and air 
cylinders 2oJ-inch diameter, for a maximum pressure of 50 
pounds; free air capacity 6540 cubic feet per minute. There 
is also an Ingersoll cross-compound steam, 2 -stage air, Class 
" HC " compressor with steam cylinders and stroke as above, 




Fig. 9. — Erecting Compressors in Manhattan Power House 
for the Belmont Tunnels. 



but with air cylinders 25^- and 16^-inch diameter, for '100 
pounds air pressure; free air capacity 1704 cubic feet per min- 
ute. Fig. 9 shows one of those compressors being set up in 
place before the house was built over it. 

On Man-O'-War's Reef there are three duplex Class " J' 
Ingersoll belted compressors with air cylinders 2oJ-inch diameter 
by 18-inch stroke, for 50 pounds pressure; aggregate free air 
capacity, 6540 cubic feet per minute; one electric belted 2- 
stage machine for 100 pounds pressure with air cylinders 254- 
and 161-inch diameter by 18-inch stroke; free air capacity, 1704 
cubic feet per minute; and two Ingersoll Class " A " straight 
line compressors, 24-inch diameter steam, 26^-inch diameter 



APPENDIX A 



199 



air, by 30-inch stroke; free air capacity, 3686 cubic feet per 
minute. See Fig. 10. 

At the Long Island City plant there are two Ingersoll cross- 
compound steam, 2-stage air Class " H " compressors with steam 
cylinders 15- and 28- by 16-inch stroke, and air cylinders 25^ 
and i6i, for 100 pounds air pressure; free air capacity, 3408 
cubic feet per minute. There are here also two Ingersoll Class 
"A" compressors 24- and 264- by 30-inch stroke, free air capac- 




Fig. 10. — Power House for Belmont Tunnels on Man-o'-War's Reef. 



ity, 3686 cubic feet per minute; and one Class " A " com- 
pressor 24- and 2-4J- by 30-inch stroke, free air capacity, 1570 
cubic feet per minute. See Fig. 11. 

Hudson Companies' North River Tunnels, Morton Street, 
Manhattan. This pair of tunnels now completed was begun, 
or one of them, a quarter of a century ago, the work having 
been stopped by serious accidents and financial difficulties. 
The final plant here comprised one duplex Rand compressor 



200 



SUBWAYS AND TUNNELS OF NEW YORK 



22- by 24-inch stroke, free air capacity 2640 cubic feet per min- 
ute; one Ingersoll Class " A " 22- and 22f- by 24-inch stroke, 
free air capacity, 1320 cubic feet; one Ingersoll 20- and 22|- 
by 24-inch stroke, free air capacity, i32 K o cubic feet per 
minute; and an Ingersoll 16- and 16 J- by 18-inch stroke, 
free air capacity, 698 cubic feet per minute. 

Hudson Companies' North River Tunnels, Fifteenth Street, 
Hoboken, N. J. This plant is located immediately opposite 




Fig. 11. — Interior of Long Island City Power House for Belmont Tunnels. 

the preceding, working at the other ends of the same tunnels 
and continuing them westward into the land. There is one 
compressor here which was sold to the Hudson River Tunnel 
Company in 1880, and overhauled in 1890, which was still 
doing good service until the work was finished. It is now 
rated as an Ingersoll Class "A", 20- and 20 J- by 30-inch stroke, 
free air capacity 1089 cubic feet per minute. There are also 
two Ingersoll Class "A" compressors, 22- and 26 J- by 24-inch, 



APPENDIX A 201 

free air capacity 2686 cubic feet per minute; and one Ingersoll 
duplex Class "H" compressor 16- and 2oJ- by 16-inch stroke, 
free air capacity, 2178 cubic feet per minute. 

Hudson Companies' North River Tunnels, Near Pennsyl- 
vania Station, Jersey City, N. J. The tunnels here being driven 
are to enter New York City near Cortlandt Street; there is no 
plant opposite, the tunnels being driven entirely from their 
western ends. There are here three Ingersoll Class " HC ' 
cross-compound steam, 2-stage air compressors for high pres- 
sure air, and three Ingersoll Class " H " cross-compound steam 
and duplex single-stage air compressors for the low-pressure 
air. The former are 14- and 28-inch steam and 24^- and 141- 
inch air by 16-inch stroke, free air capacity 4710 cubic feet per 
minute ; and the latter are of the same steam dimensions with 
air cylinders 22^- by 16-inch, free air capacity, 7920 cubic feet 
per minute. 

Hudson Companies' No. 4 Plant, Washington Street, Jersey 
City, N. J. This plant has been employed upon land tunnels 
connecting the two preceding. It comprises two Rand Class 
" B " compressors, cross-compound steam cylinders 18- and 
30-inch, and 2-stage air cylinders 26- and 15-inch by 30-inch 
stroke, free air capacity 3686 cubic feet per minute; and two 
Rand Class "B" compressors with steam dimensions as above 
and duplex air cylinders 2 3 -inch diameter by 30-inch stroke, 
free air capacity 5768 cubic feet per minute. 

Summary of Tunnel Plants. The total free air capacity 
of all the compressors here enumerated is 191,291 cubic feet per 
minute, which would be represented by a cube with a side of 
over 57 feet. The total number of compressors is eighty, 
most of them approaching the largest sizes built. The actual 
horse-power employed has not been computed on account of 
the differences in the air pressures, but probably is not less 
than 40,000. The number of steam cylinders is one hundred 
and twenty and the number of air cylinders, one hundred and 
thirty-eight. That these compressors have been kept con- 
stantly running, mostly night and day, and generally at speeds 
which would be considered excessive, is something for the 



202 



SUBWAYS AND TUNNELS OF NEW YORK 



builders, the owners and the operators to be proud of. -What- 
ever delays have occurred, whatever accidents have happened, 
whatever of the unforeseen has been encountered, the air com- 
pressors have been always ready, always efficient and always 
to be relied upon. 




Fig. 12. — One Type of Boiler Used in the New York Tunnel Plants. 



It will be seen that the compressed air for this tunnel work 
is delivered and used at two quite different pressures, requiring 
two different classes of compressors and separate pipe lines 
for transmission. The low pressure air for the shield work is 
generally used at pressures of between 20 and 30 pounds and 
the compressors are usually guaranteed for a maximum of 50 



APPENDIX A 203 

pounds. The high pressure air for operating the drills is required 
to be higher than the normal for such work, as the air from them 
is exhausted against the air pressure in the shield. The air 
for this service is carried at pressures above ioo pounds up to 
140 or 150 pounds, the compression being 2-stage with, of 
course, efficient intercooling. Many of the installations also 
include aftercoolers, which are found to contribute to economy 
of operation, giving drier air and reducing the volume during 
transmission without any ultimate reduction of volume when 
the air is used at the end of the line. 

The usual conditions of steam economy are insisted upon 
throughout these plants. Steam is carried at pressures up to 
150 pounds, the steam ends of the compressors are generally 
compounded, and condensing apparatus is usually installed 
for each entire plant whether the individual units are com- 
pounded or not. The automatic regulation of the speeds 
of the compressors according to the varying demands of the ser- 
vice has been a notable and successful feature. 

Much the larger volume of the air compressed has been for 
the low pressure service to oppose the inrush of water, and 
passengers on the East River ferries have seen the water actively 
boiling with the escape of this air, so that most of it may in 
a way be said to have been lost or wasted. Under the 
most favorable conditions the use of air in subaqueous 
tunnels is a very different problem from that of the vertical 
caisson. In the latter the pressure adjusts itself precisely 
to that of the surrounding water, the air escaping under 
the edge when the pressure is at all in excess, and the 
compressor supplying a caisson has only to make up for the 
losses in the air lock and to renew the air sufficiently for safe 
respiration. 

When the air pressure at the top of the tunnel is suf- 
ficient to balance the pressure of the water and hold it back, 
the air pressure at the bottom of the tunnel will be five or six 
pounds too light; and if the pressure is increased to balance 
the water pressure at the bottom, then it is able to blow off 
at the top with considerable force, and where the superincumbent 



204 SUBWAYS AND TUNNELS OF NEW YORK 

material is in a soft or semi-fluid condition the air finds its way 
through it in all directions. The compressors in this service 
were constantly worked to their utmost in the struggle with 
the soft mud waiting to rush in, and an unstable equilibrium 
only could be maintained at the best. — Frank Richards, in Com- 
pressed Air Magazine, January, 1908. 



APPENDIX B 

THE COMPRESSED AIR PLENUM 

The remarkable success which engineers have made in driving 
tunnels under rivers and other important waterways in various 
parts of the world, has led to a serious consideration of employ- 
ing similar methods for establishing subaqueous passages 
beneath straits, bays and even the ocean itself. From the 
constructional point of view, there is not the slightest doubt 
of its feasibility, for what has been done so satisfactorily in 
many cases can be extended to a far greater degree. 

At the present time financial reasons would alone seem 
to prevent the boring of tunnels between Europe and Africa, 
or Asia and North America, since the expense would be, perhaps, 
larger than the ultimate advantages to be secured. Further- 
more, in the face of the diplomatic relations existing between 
world powers, such engineering feats appear to be well-nigh 
impossible. However, apart from this, engineers regard with 
confidence the proposition of sub-ocean tunneling because the 
achievements already attained have been due to the develop- 
ment of the compressed air system. At first, when this system 
was introduced, its possibilities were only conjectural, for its 
beginnings were small inasmuch as it was used for driving bores, 
making foundations for bridges and wharves under river beds, 
and in waterbearing strata generally. But it has developed 
steadily, until now work is carried on with safety and with 
certainty, as regards its final result, at depths up to nearly 
1 20 feet below high- water level, involving an air pressure of 40 
pounds per square inch above the atmosphere. In fact, in 
nearly every instance where water is likely to be encountered, 
compressed air is now adopted, for engineers prefer to use it 
as a safeguard against any emergency. Whether compressed 

205 



206 SUBWAYS AND TUNNELS OF NEW YORK 

air can be applied for deep-sea boring is still largely a matter 
of experiment. Still, the shield system has operated so accurately 
in all cases with such practical results, that its application 
to engineering problems of such magnitude as referred to above 
is highly probable.* 

The phenomenal advances in the methods of subaqueous 
tunneling in the last few years are directly due to the improve- 
ments in the means of generating, and of operating with, com- 
pressed air. 

The use of the plenum method for tunneling, and in sink- 
ing caissons, has become general in submarine work. The 
air, compressed to the required pressure, provides in itself 
the power to operate the drills, shovels, pumps, jacks and shields, 
and all other machinery employed in the tunnels, as well as 
providing the necessary pressure to counterbalance the weight 
of water and material through which the tunnel is being driven; 
and at the same time, air that has been used for power is pro- 
ducing a constant ventilation and supply of fresh air to the 
workmen. 

Air, when compressed, is the only medium possessing the 
qualities which are requisite in the varied conditions and opera- 
tions of subaqueous tunneling. In the East River tunnels, 
the average total supply of free air to each heading while under 
pressure was 3550 cubic feet per minute; this included the 
compressed air used for all purposes in the headings. In blow- 
outs the maximum loss recorded was 220,000 cubic feet of free 
air in ten minutes. It is probable that 30 to 40 per cent of 
this loss occurred in the first forty-five seconds, the remaining 
loss being gradual till the supply was increased to the lowered 
pressure. 

The silt pressure was lower than the hydrostatic head at 
the crown, but if it became necessary to make an excavation 
ahead of the shield, the air pressure required was about equal 
to the weight of the overlying material, namely, the water and 
silt. The silt weighed from 97 to 106 pounds per cubic foot, 
averaged 100 pounds per cubic foot, and acted like a fluid. 

* From Compressed Air Magazine, June, 1907. 



APPENDIX B 207 

The records of the air supply proved beyond doubt that 
any supply per man beyond 2000 cubic feet had no beneficial 
effect upon health; on two occasions for two consecutive weeks 
it ran as low as 1000 cubic feet without increasing the number 
of cases of bends. 

The amount of C0 2 in the air was measured daily. The 
average ranged between 0.8 and 1.5 parts per 1000 parts. In 
exceptional cases it fell as low as 0.3, and rose to 4.0. The 
temperature usually ranged from 55 to 60 degrees Fahrenheit, 
which was the temperature of the surrounding silt; when 
grouting extensively in the long sections in rock, it varied from 
85 to no degrees Fahrenheit. The pressure of air varied from 
17 to 37 pounds. To enable the engine room force to keep 
a watch on the air conditions in the tunnel, a half-inch air 
line connected the working chambers with recording gages in 
the engine room. During the greater portion of the work in 
soft ground, a pressure was maintained which would about 
balance the hydrostatic head at the axis of the tunnel. The 
required pressure varied from 30 to 34 pounds above that of 
the atmosphere. In the event of a blow, the pressure usually 
dropped from 2 to 8 pounds and it generally took some hours 
to restore the original pressure. 

The rules observed for the prevention of caisson disease 
were, that no workman was allowed to enter the air chamber 
without having undergone a physical examination, sound 
physique being an essential requirement. The men were required 
not to enter the air with an empty stomach, to wear warm 
clothing on coming out, and to drink hot coffee. The time 
worked in the air chamber was limited to eight hours with 
half an hour for lunch, up to 32 pounds gage pressure; and two 
spells of three hours each with three hours' rest between, for 
pressures from 32 to 42 pounds; and two spells of two hours 
each for pressures greater than 42 pounds, with four hours' 
rest between. 

Medical air locks were installed, well warmed dressing rooms 
provided for the workmen, and covered gangways for access 
to the shafts. Practically no cases of bends occurred until 



208 SUBWAYS AND TUNNELS OF NEW YORK 

the air pressure reached 29 pounds, when, within a few days 
of each other, two men died. 

At 30 pounds pressure, it became customary to allow 
one-half minute per pound of air pressure in decompression. 
The lengthening of the decompression period to fifteen minutes 
reduced the number of cases of bends, and no doubt prevented 




Fig. 1. — Interior of Medical Air Lock. 

many fatal ones; but they still occurred. The percentage 
of cases in air pressures of 31} pounds for 8-hour shifts was 
no greater than the percentage in 32^ pounds for two 3 -hour 
shifts. It was, if anything, less for the longer shift. 

At atmospheric pressure, the percentage of carbon dioxide 
in the alveolar or expired air is 5.6 per cent and at a pressure 
of 2 atmospheres absolute, this is reduced to 2.8 per cent. 



APPENDIX B 209 

So the question of the percentage of carbon dioxide in the air 
of the working chamber is not important unless it approaches 
the percentage in the air cells of the lungs. To illustrate this, 
if the air-chamber is under an air pressure of 30 pounds, or 3 
atmospheres absolute, the percentage of carbon dioxide in the 
air cells is 5.6 divided by 3, or 1.86 per cent; and if the per- 
centage of carbon dioxide in the air chamber does not exceed 
1 per cent, no ill effects will arise. This is ten times as much 
as generally specified, namely one part in 1000, and greatly 
reduces the amount of compressed air necessary per man per 
hour, which can be calculated approximately from the follow- 
ing formula: 

_ , . , . 80 cubic feet 

Cubic feet per man per hour = 7^ ^r - h- 

r r percentage C0 2 permitted 

Thus, if 0.04 per cent is the C0 2 in the atmosphere, and 

the percentage in the tunnel is allowed to go up to 0.10 per cent, 

the air required per man per hour equals — 7 = I 333 cubic 

feet. 

The death rate due to caisson disease was comparatively 
small, an average of 19/100 of one per cent for the whole of the 
compressed air work. The only recognized cure for caisson 
disease is recompression in a medical air lock, followed by 
slow decompression. This makes evident the advantage of slow 
decompression; and when it is at all possible, in future works, 
regulated decompression will in all probability be adopted. 

From " Caisson Disease and Its Prevention," by Henry Japp, M. American 
Society C.E., Proceedings American Society C.E., December, 1909, where the 
subject is treated at length. 



APPENDIX C 

THE USE OF COMPRESSED AIR IN TUNNELING 

Since the first recorded experiments in air compression 
by Hero of Alexandria, and the invention of the air pump in 
1650 by Otto Von Guericke, the most decided advance in the 
principles of air compression are described in the application 
for a patent in 1829 by William Mann, as follows: " The 
condensing pumps used in compressing the air I make of dif- 
ferent capacities, according to the density of the fluid to be 
compressed — those used to compress the higher densities being 
proportionally smaller than those previously used to com- 
press it at the first or lower densities," etc. This was the pre- 
cursor of the present system of stage compression. 

In 1847 an English patent was granted to Van Rathen for 
the process of cooling the air by water in the cylinder, or by 
surrounding the vessel with cold water. He also describes a 
reservoir for storing air, a refrigerator for cooling the air after 
its compression, and a mode of heating the air to give it greater 
tension after it is compressed. 

In 1853, Piatti submitted several projects to the Italian 
ministry relative to the construction of the Mt. Cenis tunnels, 
which treated especially of the employment of water power 
to compress air for a motor for rock drills in driving the tunnels 
and for running trains through the tunnel both during and 
after its construction. Previous to this, in 1852, Colladon of 
Geneva filed his petition for a patent in Italy for the use of 
compressed air in running machine drills in a tunnel. To 
Colladon is said to be due the essential features of the com- 
pressor systems of the Mt. Cenis and St. Gothard tunnels. 
The compressor systems of Mt. Cenis were established, and the 
drills put to work, during 1861. It is stated that Colladon, 

210 



APPENDIX C 



211 







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212 SUBWAYS AND TUNNELS OF NEW YORK 

as far back as 1828, proposed to B runnel to use compressed 
air to keep the water out of the first Thames tunnel. 

In America, air compressors were first applied for purposes 
of rock drilling at the Hoosac tunnel. The first compressor 
used at the Hoosac tunnel consisted of four horizontal air 
cylinders set at right angles, run by a water turbine of 120 
h.p. and driven directly from a crank on the upper end of the 
shaft of the turbine. Of this compressor, Mr. Thomas Doane, 
Chief Engineer, says in his report for 1866: "The air com- 
pressor of four horizontal cylinders, 13 by 20 inches each, 




Ingersoll-Rand Class ■ NF-1 " Single-stage Steam-driven Air Compressor. 

referred to in my former report as about ready for use at the 
east end, has been at work night and day without cessation, 
except on Sundays, since March. It was intended to com- 
press air to 60 pounds per square inch, and has run up as high 
as 85 pounds; but as the drilling machines require air at only 
30 pounds pressure it has been run generally at that pressure. 
It was intended for a speed of i2or.p.m., but as it can easily sup- 
ply all our drilling machines, nine having been the highest 
number, at a speed of 70 revolutions, it has not usually been 
run faster. This compressor, making 70 revolutions, will fur- 
nish 148.01 cubic feet of air per minute, at a pressure of 42 
pounds." 

In selecting an air compressor, the conditions under which 



APPENDIX C 



213 



it is to operate are to be carefully considered, as it is impossible 
to design a single compressor which will fit all conditions. The 
most important factors are: Pressure desired; the character 
of apparatus to be operated; the cost of fuel; allowable space; 
and quantity of air required. Generally speaking, economy 
has not been the most important consideration until recently. 
The three classes into which reciprocating apparatus for 
the production of compressed air naturally fall, and considera- 
tions of convenience, first cost and economy of operation, have 




Ingersoll-Rand Class "O" Duplex Double Cross-compound 
Duplex Air Compressor. 

resulted in the development of certain distinct types of com- 
pressors, which may be classed under the general heading of self- 
contained steam actuated compressors, and those actuated 
by some external means. 

Both classes may be simple, duplex or multi-compression 
machines. Experience, however, has sifted out the best forms, 
which are as follows: 

(i) Straight Line; that is, steam and air cylinders in one 
line, mounted on a continuous girder frame. A 
self-contained, reliable type; a great user of steam, 



214 SUBWAYS AND TUNNELS OF NEW YORK 

but a most satisfactory type when fuel is inexpensive 
and where a large amount of air is not needed; 
usually single-stage compressors, but often built in 
two or three stages. 

(2) Duplex; usually built with two parallel engines, con- 

nected by 90-degree cranks to a single fly-wheel 
shaft, with air cylinders behind each steam cylinder. 
Both steam and both air cylinders are of the same 
diameter. This type makes no great pretense at 
economy, but finds an extensive field in locations 
where fuel is not high and where simplicity and small 
first cost are important, and where considerable air, 
at low pressures only, is desired. 

(3) Compound; of the same general character as the duplex 

except that either or both air and steam cylinders 
are compounded. In some cases the engine may be 
run condensing. This is, however, hardly necessary 
except for very large sizes, where it is far more desir- 
able to use the large class of Corliss type. 

(4) Corliss type; as implied in the name, this class includes 

compressors in which the engine portion employs 
the well-known Corliss valve motion. Such com- 
pressors, with few exceptions, are of the horizontal 
type, the air cylinder or cylinders, as the case may 
be, being placed tandem to the steam cylinders. 
They are employed where the volume of air desired 
and the fuel conditions demand the most economical 
form of engine. They are usually compounded, both 
for steam and air, and generally run condensing. 
As air is commonly used under the same conditions and 
with the same machinery that uses steam, the true way of com- 
paring the efficiency of a compressor would be to compare the 
volume of cold compressed air that the compressor will furnish 
with the volume of steam the compressor uses at the same pres- 
sure, to furnish the amount of air. On this basis, the efficiency 
of a straight line compressor, non-compound, would be about 
60 per cent.; a duplex Corliss compressor with compound 



APPENDIX C 



215 



condensing steam and compound air cylinders with inter- 
cooler, about 80 or 90 per cent, in cold air, of the amount 
of steam used. 

If the properties of cold air and steam are compared, the 
comparison is all in favor of air. The loss due to condensation 
in an exposed steam pipe line often amounts to from 15 to 30 
per cent. This loss alone would make the use of air more 
economical. 

Air pipe lines have in different places been laid for distances 
of fifteen miles or more, but average pipe lines in tunnels and 
around quarries run from 1000 to 10,000 feet. 




Ingersoll-Rand Class "CH " Corliss Steam Double Cross-compound 
Duplex Air Compressor. 



As a practical example of what would be required if 1000 
cubic feet of free air compressed per minute to 80 pounds pres- 
sure were to be carried a distance of 5000 feet, a 5-inch pipe line 
would show a loss of pressure of about 6 pounds, and a 6-inch 
pipe line about 2\ pounds, all elbows in the pipe line increasing 
the friction. The difference in the diameter of the pipes accounts 
for the difference in loss of pressure. 

The friction loss may be considered for ordinary purposes 
as being proportional to the length of pipe and to the square of 
the velocity of the air ; where the volume passing through a pipe 
is doubled, the friction will be about four times as great. 



216 



SUBWAYS AND TUNNELS OF NEW YORK 



Heating the air by means of a reheater increases the volume 
from 35 to 50 per cent; and this increase in volume costs only 
about one-sixth in cost of coal in reheating, as compared with 
the cost of coal in compressing. 

When a compound condensing compressor with compound 
air cylinders, giving 90 per cent, in air of the volume of steam 
used, has the air reheated before use, it becomes evident how an 




33/7 



Ingersoll-Rand "Imperial X" Duplex Steam-driven Air Compressor. 



efficiency 20 per cent greater than if steam were used direct 
may be obtained, in addition to the many advantages and 
conveniences in the use of air. 

From " Tunneling, Explosive Compounds and Rock Drills," by Henry S. 
Drinker, J. J. Swann in the Sibley Journal, Wm. Prellwitz in Compressed Air 

Information. 



APPENDIX D 

SPECIAL TYPES OF AIR COMPRESSORS 

Water Impulse Compressors. When water power is available 
at, or within several miles of, a plant where compressed air 
is required, the energy of the water may be employed to con- 
vert free air into compressed air at any desired pressure, and 
when piped to the works may be used for pumping, hoisting, 
drilling, and many other purposes, with considerable success and 
economy. 

Impulse wheels range in efficiency from 85 to 90 per cent, 
and insure the production of compressed air energy at a cost, 
per unit of power, lower than by any other method. 

The sizes of water wheels used depend, of course, upon the 
requirements of each separate case, as to the flow and head of 
water. Water-impulse compressors may be either of the simple 
straight line or duplex types. The straight line form is 
employed when the demand for air is light; this machine has 
the advantage of the straight line construction in that it takes 
up the stresses and strains in direct lines. The duplex machine 
is largely of service where the demand for air is considerable, 
and it has the advantage of relieving strains, by dividing the 
work equally between the cylinders; this machine is made 
with either simple or compound air cylinders, and when com- 
pounded a suitable intercooler is employed to remove the heat 
of compression, as the air passes from the low to the high pressure 
cylinders. 

" Imperial XE " Air Compressor. The illustration on page 
219 shows an Ingersoll-Rand " Imperial XE " direct-connected 
cross-compound 2 -stage electrically driven air compressor, with 
a self-starting synchronous motor on the shaft. This is one 
of the most recent developments in high-duty compressor 

217 



218 



SUBWAYS AND TUNNELS OF NEW YORK 



design, the direct motor drive having all the advantages, 
as to simplicity, compactness and high efficiency, which have 
long been recognized in direct-connected engine driven electric 
generator units. 

The features of the " Imperial XE " type are: " Imperial 
Corliss " air inlet valves on both cylinders and " Imperial 
Direct Lift" air discharge valves; wholly enclosed, dust- 




Ingersoll-Rand Class " PB " Direct-water-wheel-driven 
Duplex Air Compressor. 



proof construction; flood lubrication of all principal bearings 
from the main crank basins, the flow of oil being proportional 
to the speed of the machine and all oil being returned to the 
system; massive construction and large bearings. The direct 
motor driven compressor unit of this type, and of the same 
company's " PE " type, return the highest economy in power 
driven compressors. Methods of regulation automatically pro- 
portion power to load under all variations. 



APPENDIX D 



219 



The Taylor Hydraulic Air Compressor at Cobalt, Ontario. 

What is undoubtedly the largest single unit air compressor 
in the world is being constructed on the Montreal River at 
Ragged Chutes, about nine miles south of Cobalt, Ontario, 
Can. This plant operates on the now well-known Taylor 
system, where the air is compressed by the direct action of 
falling water. The following account may be accepted as 




Ingersoll-Rand " Imperial XE " Duplex Direct-connected 
Electric-driven Air Compressor. 



authoritative in every particular, having been prepared by 
Mr. C. H. Taylor for " Mines and Minerals," from whose pages 
it is here reproduced, somewhat abridged and rearranged. 

The Cobalt Hydraulic Power Company, Ltd., is a com- 
mercial organization formed for the purpose of selling com- 
pressed air to the various Cobalt mines. At Ragged Chutes 
there is a drop in the river of 54 feet within less than a quarter 
of a mile. This entire head is to be utilized, furnishing 5500 
h.p. and compressing 40,000 cubic feet of free air per minute 



220 SUBWAYS AND TUNNELS OF NEW YORK 

to a gage pressure of 120 pounds, which is automatically 
reduced to, and maintained at, 100 pounds when delivered to 
the various mines. The air will be transmitted through nine 
miles of 20-inch pipe, from the end of which there are two 12- 
inch branch pipe lines. About seven miles from the compressor 
there is another 12-inch branch, so that the total length of pip- 
ing, 20-, 1 2-, 6- and 3-inch, will be about twenty-one miles. 

In order to prove that this power would be a great saving 
over the present cost for compressed air, about six months were 
spent in making exhaustive tests at a number of the larger mines, 
and the reports were accepted in every case by the managers. 
The tests showed that mines could save from one-half to one- 
third by buying their compressed air rather than producing it, 
and at the same time receive the air at a constant pressure. 
In addition to the advantages mentioned, it is to be understood 
that the air, being isothermally compressed, is, of course, as 
dry as possible, thus eliminating the troubles arising from 
freezing; further, there being no oil used in compression, the 
compressed air is practically odorless and ventilates the work- 
ing faces, which is a distinct advantage. The various Cobalt 
mines will be piped independently of each other and the air 
will be sold by meter measurement or by the drill unit as a basis. 
If sold by meter, a rate of twenty-five cents per 1000 cubic feet 
of compressed air per minute will be charged, the air pressure 
being 100 pounds per square inch. The company will furnish 
in this case an automatic reducing valve, meter, and limit 
valve. When air is sold on the flat rate, the charge will be 
based on one drill per shift, the charge, however, decreasing 
with an increasing number of drills. In this case, the power 
company will supply the reducing and limit valves, no meter 
being needed. 

Great care has been taken in the installation of the pipe 
lines, to prevent leaky joints and strains on the pipe. In the 
20-inch and 12-inch diameter pipe lines, balanced expansion 
joints have been placed at half-mile intervals, and half-way 
between each two expansion joints the pipes are anchored in 
massive concrete piers to prevent their creeping. 



APPENDIX D 



221 



After passing the gates the water flows through two 16- 
foot diameter intake heads, one of which is shown in Fig. 
1 at a. In each of these heads there are sixty-six 14-inch 
diameter pipes b set in a steel disk c. Below the pipes, 
the heads gradually diminish in diameter until they become 
8 feet 4f inches, and from this point they are 15 feet 
long. In this telescopic form the heads connect with the 




Fig. 1. 

intake shafts, which are 8 feet 6 inches in diameter and 345 
feet deep, with the orifice of the head at the surface of the 
water. This arrangement permits the heads to be raised or 
lowered, to conform to the level of the water in the forebay, 
or the heads may be raised above the level of the water by air 
lifts d, thus cutting off the supply completely. The two air- 
lift cylinders d act as governors, automatically raising and low- 
ering the heads which are suspended from them by the hangers 
6, thereby regulating the flow of water into the intake pipes b, 



222 



SUBWAYS AND TUNNELS OF NEW YORK 



according to the demand. The head-pieces were especially 
designed to meet conditions due to extremely low temperatures. 
The gate / is raised by rack and pinion, and there is the usual 
rack g to prevent floating material from entering the head- 
pipes. 

The water, with the entrained air, flows through the heads 
with a descending velocity of from 15 to 19 feet per second, 




Fig. 2 



gradually diminishing in the velocity of fall, owing to the com- 
pression of the volume of air; finally there is a further reduction 
in velocity owing to the enlarged section of the last 40 feet of 
fall, shown in Fig. 2. By the time the water reaches and strikes 
the steel-capped concrete diverting cones a, its velocity is so 
diminished by the baffle from the compressed air that there is 
little shock. 

The cones a are for the purpose of spreading the flow of 
air and water, thereby bringing the air nearer to the top of 



APPENDIX D 223 

the tunnel. The air being lighter than the water, it rises to 
the surface of the water under a pressure of 120 pounds per 
square inch. The tunnel was made 20 feet wide, 26 feet high, 
and 1000 feet long, the latter for the purpose of utilizing the 
total head of the stream, although this length was not necessary 
in order to give the air time to leave the water before the latter 
started up the outlet shaft b. As the velocity of the water in 
the tunnel is about 3 feet per second, practically all the air 
will leave the water in the first 300 feet. The last 75 feet of 
the tunnel has the height reduced to 16 feet. 

The pressure given to the air is due to the height of the 
body of the water in the outlet shaft, which, in this case, is 298 
feet deep and 22 feet in diameter. The water flows along the 
tunnel and up the outlet to the river, the difference in elevation 
between the mouth of the intake and the discharge tunnels 
being 47 feet. Near the outlet end of the tunnel its height is 
increased to 42 feet, and at this place two pipes are carried 
through the 30-degree riser c to the uptake shaft. One pipe 
d, 24 inches in diameter, carries the compressed air to the sur- 
face, where it is connected with the 20-inch main air pipe line. 
The other pipe e is 12 inches in diameter and has its end sub- 
merged at a safe distance above the roof of the outlet portion 
of the tunnel, to act as a blow-off in case the air in the tunnel 
should acquire such pressure as to force the water below the 
level of the tunnel outlet. If the air were allowed to escape 
up the outlet it would lighten the column of water in that shaft, 
and the air pressure would not be constant. The blow-off 
pipe ends at the upper level of the water in the outlet shaft, 
its end remaining open to the atmosphere. When the volume 
of air is greater than the demand, the air accumulates in the 
upper part of the tunnel, forcing the water down and exposing 
the lower end of the blow-off pipe e to the compressed air, thus 
allowing a portion of the water in this pipe to drop back, thereby 
decreasing the weight of the remaining water in this pipe to 
less than the pressure of the air. The equilibrium is now over- 
come and the water in the pipe is driven upward to the surface, 
where a most spectacular sight is witnessed, as the body of 



224 SUBWAYS AND TUNNELS OF NEW YORK 

water is shot out by the air sometimes to a height of 500 feet. 
The blow-off continues until the pressure of the air in the tunnel 
is sufficiently reduced to again submerge the end of the pipe. 
Water now rises until an equilibrium is established between the 
air and the water pressure in the tunnel. The air pipe and the 
blow-off pipe are packed in concrete the entire length of the 
30-degree riser, in order to seal them in and prevent any escape 
of air up the outlet shaft. Thus these arrangements permit 
the delivery of a large body of air at a constant pressure at all 
times. Compressed Air Magazine, June, 19 10. 

Lack of Oxygen in Hydraulic Air at Cobalt. When the 
air from the hydraulic air compressing plant at Ragged Chutes, 
Cobalt district, Ontario, was first turned on it was found that 
it was difficult to burn candles in the mines where it was used. 
It was claimed that this was due to the absorption of oxygen 
by the asphalt with which the inside of the pipes was coated, 
and that this effect would soon pass off. It was soon found, 
however, that hydraulic air contains an appreciably less per- 
centage of oxygen than ordinary air, and analysis demonstrated 
that it contained only 17.7 per cent oxygen, which is 3 per cent 
lower than ordinary air. This is due to the oxygen going into 
solution in the water during compression, when a pressure of 
130 to 135 pounds per square inch is maintained. The lack 
of oxygen does not apparently trouble the miners, but besides 
the difficulty experienced in keeping lights, the effect of the 
gases from exploded dynamite is more serious than was found 
to be the case with air compressed by machinery. Engineering 
and Mining Journal. Compressed Air Magazine, August, 19 10. 

Cost of Hydraulic Air Compression. The Taylor system of 
air compression, adapted to the development of waterfalls of 
moderate height and copious volume, has elicited much favorable 
comment, and where it has been installed it has been completely 
successful so far as the actual compressing of the air is concerned, 
but the cost which seems inevitable in its installation is not 
so familiarly known. The following account of one plant is 
given by Mr. Geo. C. McFarlane in Mining and Scientific Press. 

" The most recent installation is a 5000 h.p. plant now 



APPENDIX D 225 

about completed at the Ragged Chutes of the Montreal River, 
nine miles south of Cobalt, Ontario. Work has been in progress 
on this installation for three years and for the past year a force 
of 200 or 300 men has been employed. The Montreal River 
has here, in about 1000 feet, a drop of 28 feet. The power 
people built a concrete jetty into the middle of the river and, 
to protect the opposite bank from cutting, built a concrete wall 
in a trench a few feet back and parallel with the bank. During 
the high water this summer (1909) the river current, thrown 
sideways by the jetty, gouged into the opposite bank as far as 
the concrete wall and partly undermined it, which illustrates 
one way of how not to attempt to raise the level of a swift river. 
" Just below the jetty, at the head of the rapids, are two 
shafts, steel-lined, 16 feet in diameter and 360 feet deep. A 
20- by 26-foot tunnel, 1000 feet long, connects these shafts with 
the uprise shaft at the foot of the rapids. The air is compressed 
to 140 pounds and is conducted to Cobalt by a 20-inch pipe. 
The pipe was made in 40-foot lengths, with welded flanges and 
sliding expansion joints set in concrete pits every half mile. 
Aside from the transmission pipe lines I would estimate the 
cost of the plant at the chutes as not far from $1,000,000. 
This makes the cost per horse-power for installation about 
$200.00 which does not compare favorably with the cost of an 
ordinary air plant. I know of two small plants that were installed 
for less than $90.00 per horse-power, including flume and pipe 
line, as well as wheel and compressor." Compressed Air Maga- 
zine, April, 1 9 10. 



APPENDIX E 

STRAIGHT LINE AND DUPLEX COMPOUND AIR COMPRESSORS 

There is nothing new about the higher expansion process, 
as applied to marine engines, pumping plants and general power 
service. But while, in the engineering world, general practice 
has settled down to a true appreciation of the practical value 
of correct steam compounding, there still is much to be said on 
this subject in its relation to the economical compression of 
air and gas. 

Marine engines are almost invariably compound or triple 
expansion. Such engines work under high pressure, operate 
condensing, and run under a constant load. Compound steam 
cylinders are also common on pumps, even when run non- 
condensing, and with ordinary steam pressures. But here 
again is the feature of constant load. Steam engines for general 
power purposes are usually compounded if the units are large 
and condensing is practicable, but in small and medium sized 
units it seems generally understood that, unless pressure is 
high or condensation easily available, compounding is of doubtful 
value because of the great load variations. 

In the case of the air compressor, the conditions approach 
those of the first two instances cited, but differ radically from 
the latter instance. These conditions are such as to make 
the compounding of steam cylinders desirable in every sense 
of the word, even where steam pressures are only moderate 
and condensation not always practicable. The discussion 
following will make this point more clear and may throw a new 
light on the subject of compressor economy to those not intimately 
familiar with compressor practice. 

226 



APPENDIX E 227 

The advantages of compounding in steam engine practice 
everywhere are so familiar as to require not even a repetition 
here, but its special value in air compressing practice seems 
not to be fully appreciated. In view of the number of steam 
driven compressors in use which are neither compounded nor 
condensing, it seems that it is not generally understood that, 
while a saving of 10 to 15 per cent of the power cost is possible 
at the air end of the compressor by compounding, a saving of 
about double that percentage in fuel cost, 20 to 30 per cent, 
is easily possible by compounding the steam end of the same 
machine. If compound compression is economically practical, 
why neglect a saving twice as great possible by compound steam 
expansion? 

This neglect is especially remarkable in view of the fact 
that the air compressor embodies load conditions which make 
the compounding and condensing of steam cylinders even more 
economically desirable than in general steam engine practice. 
Compound steam driven air compressors can show better results 
than compound stationary engines for power purposes, and for 
a very simple reason. To get all the economy possible from 
the steam, it must be admitted to the first cylinder in just such 
quantity that when it is finally expanded into the low pressure 
cylinder, its pressure there shall be such as to avoid excessive 
expansion and consequent heavy condensation losses. This 
means, of course, the admission of the same quantity of steam 
per stroke, for each stroke, implying a cut-off constantly fixed 
very close to the right point. This is entirely impossible with 
the stationary engine, where the constant speed under varying 
load must be maintained by a constantly changing cut-off r 
this cut-off being automatically controlled by the governor, 
and necessarily having a wide range to meet load conditions. 
There can be only one best point of cut-off, and departures 
from that necessarily impair the ultimate economy. 

In the case of the air compressor the load is constant per 
stroke; for the same delivery pressure must be maintained, 
and the cylinders can be so proportioned and the cut-off so 
set as to secure and maintain the best results. The governing 



228 SUBWAYS AND TUNNELS OF NEW YORK 

variations of the steam driven compressor are as to speed only, 
and, with air pressure constant, the changes in speed are made 
either by a very slight change of cut-off or with a throttling 
governor. In the latter case the slight " wire drawing " is 
about offset by the resultant superheating of the steam. As 
a result of these conditions the compound compressor can be 
made to work close to its best economy at all times. 

The steam pressure used has an important bearing upon the 
ultimate economy. Within practical limits, the higher the 
pressure, the better the results. Gage pressures of 125 to 150 
pounds are now quite common in new installations; but in air 
compressor practice, steam compounding is advantageous with 
steam at 80 pounds condensing, or 90 pounds non-condensing, 
though this may not be at all true in general power practice. 
When, as is often the case where compressors are used, water 
is costly, the smaller amount required by the compound is an 
argument for it; and the ultimate cost of the arrangement 
is also largely offset by the reduced cost of boiler installation 
and operation, due to the lower steam consumption. 

It is unnecessary at this point to enter into a discussion of 
the phenomena of the application of power to resistance in 
compressor work. It will be enough to mention and to draw 
briefly the distinction between the two standard types of air 
compressors, designated as the straight line and duplex. In the 
former, steam and air cylinders, whether simple or compounded, 
are arranged in a straight line, and power is applied to resistance 
through the medium of one long piston rod. In the duplex 
machine there are two elements set side by side, each made 
up of a steam and an air cylinder, and each element in effect 
a straight line machine. However, the cranks of these two 
sections are set at an angle of 90 degrees, or one-fourth part of 
a circle, on the shaft. The primary object of this quartering 
crank arrangement is to secure a more uniform rotation effect, 
and to improve the regulation qualities of the machine by 
making it easier to run at slow speeds through the mutual 
assistance of the two sides. The straight line compressor may 
have two, three or four cylinders, but they must all be arranged 



APPENDIX E 229 

in a straight line or " tandem " to one another. The duplex 
compressor must have four cylinders. 

It is an interesting thing that when four cylinders are 
adopted in a duplex, to secure a more uniform rotation effect 
and to make it possible to keep running at the lowest speeds, 
the compounding of the cylinders helps to promote the original 
purpose of the duplex arrangement. At the steam end, because 
of the higher terminal pressure, the variation in working pres- 
sure is less. The result is that the effective pressure for the 
stroke is more uniform and continuous, and the rotation effect 
produced from the beginning to the end shows less difference 
than when the steam is used in a single cylinder. The differ- 
ence of pressures in the low pressure cylinder is less for the same 
reason. 

Aside from this reduction in range of cylinder pressures, 
the differences in temperatures are a powerful element in 
economy. These two features will be more clearly understood 
by a brief consideration of a specific case. 

Assume that the initial steam pressure is 145 pounds gage, 
or 160 pounds absolute, and that a condenser gives a terminal 
cylinder pressure of, say, 10 pounds absolute. Ignoring for the 
sake of clearness the effects of clearance, condensation, etc., 
there are seen to be sixteen expansions of the steam. In com- 
pound steam cylinders, properly proportioned, this means four 
expansions in each cylinder. In the high pressure cylinder, the 
initial steam pressure will be 160 pounds and the terminal 40 
pounds; the initial temperature will be 363 degrees and the 
terminal 267 degrees Fahrenheit. The difference in pressure 
is thus 120 pounds and in temperature 96 degrees. In the 
low pressure cylinder, initial and terminal pressures will be 40 
and 10 pounds, respectively, corresponding to temperatures 
of 267 and 193 degrees Fahrenheit. The difference in pres- 
sures is here 30 pounds and in temperatures 74 degrees. 

If this expansion had been applied in a single cylinder, 
the range of pressures would have been 150 pounds and of tem- 
peratures 170 degrees Fahrenheit. Evidently the use of com- 
pound steam cylinders in this case reduces, by approximately 



230 SUBWAYS AND TUNNELS OF NEW YOKK 

one-half, the cooling effect to which cylinder walls, ports, valves, 
etc., were subjected by the drop in temperature through expan- 
sion. The steam consumption in the former case would have 
been correspondingly less, and the effect of temperatures on 
steam economy is apparent. If a condenser had not been used, 
the range of pressures and temperatures would not have been 
so great, but, relatively, as between compound and simple 
cylinders, the same comparison would hold. 

Looking now at the air end, the phenomena and advantages 
of compound air compression are so well understood as to need 
no extended discussion here. It will be enough to emphasize 
the fact that in the air cylinders inversely the same things are 
true of pressures and temperatures as have already been noted 
in connection with the steam cylinders. The result is a reduc- 
tion in the differences of temperatures and pressures in the air 
end, all tending toward an improved operation. The cutting 
down and transferring of the excessive uncompensated pres- 
sures in the cylinders from the extreme ends of the stroke, and 
their more uniform redistribution secured by this process of 
double compounding, reduce the terminal and maximum stresses 
upon the bearings about 45 per cent., noticeably improving 
running conditions, making the lubrication easy and more 
effective, reducing wear, and giving greater durability, while 
still dispensing with the necessity for close attention. 

Straight line compressors have been made with tandem 2- 
stage air compressing cylinders, and even also with tandem 
high and low pressure steam cylinders; but these arrangements 
have greatly complicated the machine, have increased its relative 
cost for the work it does, have made all the parts more inaccessible 
than before for adjustment, repair or replacement, and after all, 
have left the machine, in its actual running, defective in its 
characteristic inability to run at slow speed, and to get the 
expected results at any speed. 

In the duplex machine, as compared to the simple straight 
line type, while there is a simplification by a reduction of the 
number of parts as regards fly-wheel, crank shaft and connecting 
rods, there are four cylinders in place of two. But here is 



APPENDIX E 231 

where one of the most important of the advantages of the 
duplex machine is found. It happens that this very arrange- 
ment at once provides the possibilities for the best economy 
both in the development of the power from the steam and 
in the application of the power to the compression of the air, 
simply by virtue of its four cylinders. To use steam with 
the best economy, in this line of service, high steam pressure, 
compound steam cylinders, and a condenser should be used. 
These conditions, except the latter, may be provided for in new 
installations; the latter depends upon the water available. 
To compress the air to the usual pressures and with the least 
expenditure of power, compound air cylinders with an efficient 
inter cooler between must also be provided. An economical 
air compressor of the present day, cannot, therefore, have less 
than two steam and two air cylinders ; and if the duplex machine 
thus insists upon four cylinders, it insists only upon one of the 
most important conditions of practical economy in air compres- 
sion. If it insists on a larger floor space, it distributes itself so 
well as to fully offset this factor by its better " get-at-ableness." 
The duplex compressor makes possible the compounding 
of the cylinders either at the air or steam end, or both, without 
additional complication. The cylinders are there, and in the 
precise relative conditions most suitable for compounding. 
Duplex compressors may be, and are, actually made either 
duplex steam and duplex air, duplex steam and compound air, 
compound steam and compound air, or compound steam and 
duplex air. The third arrangement is, of course, the ideal 
combination for satisfactory and economical air compression, 
when steam and air pressures are not too low. The location 
of the cylinders and other parts relative to each other is 
precisely that most convenient for locating and connecting steam 
receivers, air intercoolers, aftercoolers, and other appurtenances. 
The attitude of the duplex machine is to invite, to make easy, 
and to promote the best practice in air compression. The 
attitude of the straight line machine, on the other hand, is 
just as distinctly to make difficult, and in some details, impossible, 
the same advanced and most approved practice. 



232 SUBWAYS AND TUNNELS OF NEW YORK 

It is really a striking array of advantageous features which 
can be brought out in favor of the duplex type of air com- 
pressor. The following may be recalled among them: Greater 
economy in steam consumption; gains by compounding both 
steam and air cylinders; the maintenance of a more uniform 
air pressure ; the delivery of dry air ; automatic control and effi- 
cient lubrication; reduced leakage by the partial balancing of 
pressures; low friction of valves and pistons; sustained adjust- 
ment and tightness of vital parts. These may easily result 
in a saving of 30 to 40 per cent over the simple straight line 
machine, and of 15 to 20 per cent over the double -compound 
straight line. Then the reliability and perfect accessibility 
of every part, and the saving in supervision and maintenance, 
are also to be considered in its favor. For the straight line 
it can be said that the first cost is perhaps less, the foundations 
required are less expensive, and the space occupied is small. 
The saving in operating the duplex machine will really cover 
the difference in these costs many times over and, before long, 
entirely pay for the machine. 

Figures will actually show that the difference in the first 
cost of the machine and its installation is returned in a few 
months without any but the ordinary conditions as to fuel 
and labor costs. 

Take an average case in which the power consumption is 
but 500 cubic feet of free air per minute, compressed at sea 
level to 90 pounds gage. In a single stage compressor this 
will require 94 indicated horse-power; in a 2-stage machine, 
81 indicated horse-power. A straight line compressor of this 
size is usually operated with a simple steam cylinder; and while 
such machines are usually equipped with Meyer gear permitting 
economical cut-off, yet the practical running conditions of a 
straight line are such that not one out of a hundred are, in 
actual service, run at less than five-eighth to three-quarter 
cut-off. This is a fact of experience and its result is that straight 
line machines of this size take, in every-day service, from 40 
to 50 pounds of steam per horse-power hour, and every well- 
informed engineer knows that they will require on an average 



APPENDIX E 233 

of 45 pounds of steam or water per horse-power hour. The 
duplex, having no "dead center," can be run conveniently at 
short cut-offs; and in ordinary compressor service, small units 
and moderate steam pressures, duplex compound steam cylinders 
will require about 28 pounds of steam per horse-power hour, 
non-condensing. 

These relative figures are as fair to one as to the other ; not 
the best that can be done, but what can actually be expected 
under ordinary conditions for a term of years. 

An average boiler plant will not do better than 7 pounds 
of water evaporated per pound of coal burned. A boiler 
horse-power is rated as 30 pounds of steam evaporated per hour. 
These are average figures, and comparisons based on them are 
safe and fair to all. 

Results in the present case may be tabulated thus: 

Simple air and simple steam: 94 indicated horse-power; 
multiplied by 45, equals 4230 pounds of steam per hour; divided 
by 30, equals 141 boiler horse-power. 

Two-stage air and simple steam: 81 indicated horse-power; 
multiplied by 45, equals 3645 pounds of steam per hour; divided 
by 30, equals 122 boiler horse-power. 

Duplex 2-stage air and compound steam: 81 indicated horse- 
power; multiplied by 28, equals 2268 pounds steam per hour; 
divided by 30, equals 76 boiler horse-power. 

Saving by compounding air end alone (straight line or 
duplex): 13 indicated horse-power; 585 pounds of steam per 
hour, 19 boiler horse-power. 

Saving by compounding steam end alone (duplex cross- 
compound steam simple air): 1377 pounds of steam per hour; 
46 boiler horse-power. 

Saving by compounding steam and air (duplex double- 
cross-compound only): 13 indicated horse-power; 1962 pounds 
of steam per hour; 65 boiler horse-power. 

These figures alone are enough to prove the case, but the 
buyer of machinery thinks in dollars and cents rather than in 
horse-power. He is, to be sure, interested in knowing that the 
duplex compound is " more economical of power," but he knows 



234 SUBWAYS AND TUNNELS OF NEW YORK 

that " it costs more " than the straight line; and even a full 
knowledge of the fact that the straight line " double-compound " 
is mechanically inferior to the duplex or " double-cross-com- 
pound " may not overcome his financial scruples. 

But a complete compressor plant includes boilers and 
auxiliaries as well as the compressor; and boilers cost money, 
besides having a voracious appetite for coal. It has been 
demonstrated that a " double-compound " straight line is not 
a satisfactory machine; so further comparisons, reduced to 
money values, may be based on a simple steam 2 -stage straight 
line and a " double-compound " of duplex type. 

To use this straight line machine, 46 additional boiler horse- 
power, with larger piping, auxiliaries, etc., must be purchased. 
The buyer, referring to his catalogue table, will see 81 h.p. 
noted, but will not notice that this is indicated horse-power, 
and at a rating of only 30/45, or two-thirds of the boiler 
horse -power required. So he will probably buy a 90 h.p. boiler, 
force it up to 122 h.p., and then wonder why it fires so hard. 
This same inference made in buying a " double-compound '" 
would have resulted in getting a good, easy-firing boiler, prob- 
ably never loaded to its full capacity. The simple steam 
straight line, therefore, must be charged up with the cost of 46 
additional boiler horse-power, with necessary auxiliaries. If 
their price installed is put at the moderate figure of $10.00 per 
horse-power, not including cost of auxiliaries and larger piping, 
there is a total of $460.00, which, credited to the first cost of 
the duplex double-compound, does not make the latter look so 
dear after all. In this particular size of compressor it will, 
probably, more than cover the difference in price of the two 
types. These are installation charges appearing in the items of 
" first cost." 

Looking now at the operating charges, it will be noted 
that 1377 pounds less water per hour is required by the duplex 
compound. This is 1650 gallons per 10-hour day. In some 
places water charge is a serious item ; at 30 cents per thousand 
gallons this compressor saves in water about 50 cents a day, 
or $150.00 per year of 300 days. When water is bad, the less 



APPENDIX E 235 

there is to be handled, the less boiler repairs involved. In a 
larger plant, the labor of a fireman may also be saved. 

The value of the water saved is important, but the amount 
of coal otherwise needed to evaporate this extra water is still 
more important. At i pound of coal per 7 pounds of water 
evaporated, this 1377 pounds would require 197 pounds of coal 
per hour, or 1970 pounds per day of 10 hours. With coal at 
$4.00 per ton, this is $3.94 per day or $1182.00 per year of 300 
10-hour days. The amount saved by the use of the duplex 
cross-compound in fuel and water, therefore, is $1332.00 per 
year. In five years this amounts to $6660.00; and if the plant 
runs double-shift the figure is doubled. Further, as these figures 
are based upon only 500 cubic feet capacity, it can be estimated 
approximately for larger volumes. For example, 750 cubic 
feet equals one and one-half times, 1500 cubic feet, three times 
these figures, etc. 

Where, now, is the economy of " the cheaper machine?" 
Even with coal at $2.00 per ton, or only half the figure assumed 
above, the saving per year in fuel and water appears at $741.00; 
and the duplex compound is obviously the thing, for this amount 
will more than overbalance the difference in cost between the 
two types. Even at this fuel rate its total first cost would be 
saved in a few years; it would pay to throw out at once a less 
efficient machine. When coal is at all expensive, it is evident 
that the buyer should go on to the most refined Corliss type of 
compressor, running on only about one-half the fuel required 
by even the good duplex double-compound used in the example — 
and 500 cubic feet per minute is not a large machine. 

It must, however, be kept in mind that to secure these 
savings it is not enough that a compressor be of the " double- 
compound " type; but it must be a thoroughly high-class and 
really economical machine, well and properly designed, and 
well built. As there are good watches and cheap watches, 
so are there degrees of quality in all things. As a matter of 
fact, a really high-class straight fine compressor has been shown 
by accurate tests actually to deliver its output of air at less 
fuel cost than duplex compounds which, on the outside, bear 



236 SUBWAYS AND TUNNELS OF NEW YORK 

the appearance of economical design, and are even sold under 
" guarantee." Guarantees are of little protection, for once 
the expenses of foundations, piping, installation, etc., are 
incurred and the work has become dependent upon the continued 
use of the air, tests are not made once in a thousand times; a 
condition exists of which the average manufacturer is quite 
willing to take advantage even with impossible guarantees. 
If economy is really wanted, it can safely be expected and 
maintained only in constructions of the highest standard. 
— Lucius I. Wightman, E.E. 



APPENDIX F 

COMPOUND AIR COMPRESSION 

It is well known that the heating of air produces an increase 
in its volume. This is true whatever the source of the heat. 
The heat produced in a cylinder by compression acts to expand 
the air in that cylinder, whatever may be the speed or rate of 
compression. In effect, this is equivalent to an increase in the 
volume of air being compressed and delivered. This in turn 
calls for an increase in the power to compress this apparently 
added volume of air; or, to put it differently, the heat of com- 
pression, in increasing the volume of air, makes it necessary 
to carry the air to a higher average or mean effective pressure 
in the cylinder in order to secure finally the required volume of 
air at the required pressure, after its temperature has fallen 
to that of the surrounding atmosphere. Looking at it in this 
way also, there is seen to be an excess of power required to meet 
the extra resistance mentioned. 

A consideration of these facts suggests that if some means 
be provided for removing this heat of compression as fast as 
produced, there will be an important reduction in the power 
required to raise a given weight or volume of air to a given 
pressure. 

When air is compressed in a cylinder without any attempt 
whatever to remove the heat produced, the compression is known 
as " adiabatic." When compression is carried on in such a way 
that heat is removed as fast as produced, the compression is 
called " isothermal." In the first case the air delivered under 
pressure will be at the high terminal temperature correspond- 
ing to that pressure. In the second the compressed air will 
have the temperature at which it entered the cylinder. The 
first kind of compression is the one which all pneumatic engineers 

237 



238 SUBWAYS AND TUNNELS OF NEW YORK 

seek to avoid; the second is the impossible ideal. The actual 
results secured in the best compressors are intermediate between 
these, but nearer to the adiabatic. 

Other things being equal, the economy of an air compressor 
is proportional to the degree in which the heat of compression 
is removed as developed. Compressor efficiency, therefore, 
may be said to depend upon the effectiveness of the cooling 
devices adopted, provided what is gained here is not elsewhere 
wasted in whole or part. After long experience, bitter alike 
to makers and users, modern practice in compressor design 
recognizes only two practical methods of removing the heat 
of compression, viz., jacket cooling and intercooling. These 
will be considered in order. 

Jacket cooling seeks to remove the heat of compression, 
as it arises, through the cylinder walls which are kept at a low 
temperature by cold water circulaing in a surrounding jacket. 
A brief consideration of the conditions will show that jacketed 
barrel cooling alone can be only a partial and very unsatis- 
factory solution of the problem. 

With the piston at the beginning of its stroke, the maximum 
cold cylinder surface is exposed and the cylinder is filled with 
air at its lowest pressure and temperature. As the piston 
advances, pressure and temperature increase, while the exposed 
area of cooling surface diminishes; and when the maximum 
pressure and temperature are attained near the end of the stroke, 
there is practically none of the cylinder walls exposed except 
on the other, or intake, side of the piston; and if the head, too, 
is jacketed, it alone remains to exert any cooling influence. 
Furthermore, throughout the stroke only the outside layer of 
the air can be in contact with the cold surface and, air being a 
poor conductor of heat, none of the heat from the interior of the 
air volume is absorbed in the cooling water. Cylinder jacketing 
is advisable and even essential, in keeping the metal of the work- 
ing parts at a low temperature, preventing the coking of lubricant 
upon the cylinder walls, and other evils of a hot machine. But 
it cannot of itself be considered as an adequate solution of the 
problem of cooling during compression. 



APPENDIX F 239 

However, in those constructions involving the use of a piston 
inlet tube and valve, not only the barrels, but the heads and inlet 
valves, too, are chilled; and the piston and tube themselves 
are kept relatively very cool. Thus the air enters through 
a cold passage, is in contact on all sides with cold metal through- 
out the stroke, and the maximum effect obtainable from jacket- 
ing alone is secured. 

If, at several points in the stroke, the piston should be 
stopped for a moment and the air, already partially compressed 
and heated, be withdrawn long enough to be cooled by some 
external means to its initial temperature, and then returned 
to the cylinder to be further compressed, it is evident that a 
fairly uniform temperature could be maintained in the air 
volume throughout the range of pressures from initial to ter- 
minal. The result would in effect be nearly that of isothermal 
compression. Evidently mechanical considerations forbid in 
practice such repeated starting and stopping of the piston; 
but the same results may be secured by carrying on the proc- 
ess of compression in several cylinders, in the first of which 
a certain low pressure is reached and the air at this pressure 
discharged through a cooling device to a second cylinder; there 
it attains a still higher pressure and is discharged through 
another cooler to a third cylinder for a further compression; 
and so on, until the required terminal pressure is secured. Such 
a process developed to a practical working basis is the " com- 
pound " method of compression in multi-stage cylinders which 
has to-day become practically standard in air compressor work 
for the higher pressures. 

Theoretically, there is a gain in compound compression, 
whatever the pressure. But with low pressures the saving is 
so small as to be offset by the greater expense and complica- 
tion involved in several cylinders and the losses unavoidable 
in the operation of added parts. After extended experience, 
makers of air compressors have fixed upon 70 to 100 pounds 
gage as the maximum terminal pressure which can be best 
attained in simple cylinders; and for pressures from 75 pounds 
up, they have adopted compound compression in 2-, 3- and 



240 SUBWAYS AND TUNNELS OF NEW YORK 

4-stage machines, the number of stages increasing with the 
pressure. At high altitudes, however, with large volumes and 
expensive fuel, this dividing line may come at a lower pressure. 
It is elastic and depends somewhat on the conditions. 

In a compound air compressor, correctly designed, the 
cylinder ratios are such that the final temperatures and mean 
effective pressures are equal in all cylinders, and all pistons are, 
therefore, equally loaded. The air compressed in the first 
cylinder to a pressure determined by the cylinder ratio is 
discharged through the outlet valves to an intercooler, where 
it is split up into thin streams passing over cold surfaces. The 
best practice involves a nest of tubes through which cold water 
circulates, and over and between which the stream of air passes, 
complete breaking-up and subdivision of the stream being 
secured by baffle-plates and the tubes themselves. In cases 
of very high pressure the air may pass through the tubes, for 
structural reasons. A properly designed intercooler having 
sufficient cooling area for the volume of air may reduce the tem- 
perature of the air compressed in the first cylinder to at least 
outgoing water temperature. 

From the intercooler this air, entering the second cylinder 
cold, is compressed to a higher pressure and again reaches a 
temperature about the same as that attained in the first cylin- 
der. In 2 -stage machines this air will be discharged directly 
to the receiver without further cooling, unless conditions are 
such as to render advisable the use of an aftercooler. In 3- 
stage machines the second cylinder will be known as the inter- 
mediate, from which the air will pass to the second intercooler, 
undergo a second reduction of temperature, and enter the 
third cylinder for final compression to required pressure. 

It is seen that multi-stage compression is in effect identical 
with that theoretical process suggested above, in which the 
compressing piston was stopped and the air cooled at intervals 
during the stroke. The maximum cooling effect and saving 
is secured by making the intercoolers of ample proportions 
and providing for the splitting-up of the air stream into thin 
sheets exposed to cooling action. 



APPENDIX F 241 

The discussion thus far has dealt with the theory of com- 
pound air compression, the conditions encountered, and the 
means adopted in the best practice for meeting these conditions. 
General statements of the gains secured by compounding have 
been made. It remains to discuss in detail some of the more 
important and specific advantages arising from stage com- 
pression. 

The table appended (see page 347) gives the percentage of 
work lost in the heat of compression in one, two, three and four 
stages, at various pressures. In these figures no account is 
taken of jacket cooling, for the reasons already stated; nor is 
any allowance made for certain inevitable mechanical losses. 

Taking a specific example, the saving by compounding strik- 
ingly appears. Assume that a volume of compressed air equiv- 
alent to 100 final effective horse-power is be delivered at a 
pressure of 100 pounds. Referring to the table, in column two 
the theoretical percentage of lost work in 1 -stage compression 
is given at 36.7 per cent; but because there is bound to be some 
radiation of heat, this value of 36.7 per cent will not be found 
in practice, and 30 per cent may be assumed as a good practical 
value for the loss under average conditions. On this basis it 
is found, in the present case, that to deliver 100 available horse- 
power in compressed air at 100 pounds pressure by 1 -stage com- 
pression, there will be required 130 indicated horse-power. 
Looking now at column four of the table, the percentage of loss 
in 2-stage compression at this pressure is found to be 16.9 per 
cent, which is very close to the value which will be found in 
practice. Applying this value, it is seen that to deliver the 
equivalent of 100 effective horse-power in air at 100 pounds 
pressure by 2-stage compression, about 117 indicated horse- 
power will be required. In this case, as between single and 
2-stage compression, we have a direct saving of r3 indicated 
horse-power, or 10 per cent. Referring to column six, the per- 
centage of loss at roo pounds pressure in 3 -stage compression 
appears at 1.09 per cent, showing rrr indicated horse-power 
required in this case. Comparing this with the power required 
for the same work in single-stage compression, the saving appears 



242 SUBWAYS AND TUNNELS OF NEW YORK 

as 19 indicated horse-power, or 14.6 per cent. Considering the 
compression of the same volume to the same pressure in four 
stages, the percentage of loss is seen to be 7.8 per cent from 
column eight, implying an applied power of 108 indicated horse- 
power. In this case the saving, as compared to single-stage 
compression, is 22 horse-power, or 16.9 per cent. 

From these gains something must be allowed for the fric- 
tion of extra mechanical parts and of the air through additional 
sets of ports, valves, coolers, etc. More especially is this true 
when the machine belongs to that class of machine termed 
" compound " by courtesy, attractive in price through frugal 
designing, in which small coolers, insufficient valve area, 
the use of a hot discharge port for the air intake, small ports, 
etc., are all antagonistic to economy. 

Reliable and repeated tests show that such machines may 
actually require 10 to 15 per cent more power per cubic foot 
of air really delivered than some well-designed, simple, single 
cylinder types. No more cylinders are required for the com- 
pound than for the simple machine, in duplex constructions. 
Yet, here, too, the economy expected is only realized from 
high-class designs generously proportioned, and fitted with large 
coolers and the other essential refinements of good practice. 

When compression is carried on in a single cylinder, the 
difference in the pressures at the beginning and end of stroke 
is the total difference between initial and terminal pressures, 
implying a great variation in strains on the driving mechanism 
and the structure of the machine. The greatest strains come 
near the end of the stroke and are almost instantly relieved 
when the inlet valves open. Thus the terminal stress on a 
20-inch cylinder having 314 square inches area at 100 pounds 
pressure will be 31,400 pounds or nearly 16 tons. At 100 
revolutions this stress is repeated 200 times per minute and 
demands a very rugged construction. This is a condition 
not conducive to easy operation in any but the most massively 
proportioned compressors. In compound compression, on the 
other hand, the difference between initial and terminal pres- 
sures in each cylinder is but a fraction of the total range of 



APPENDIX F 243 

pressure. The pressures, furthermore, are partially balanced 
in the several cylinders. The working strains on valves and 
other parts are consequently greatly diminished, resulting in 
a greatly reduced wear and liability to breakage, and securing 
free lubrication and a noticeable improvement in the smooth, 
easy operation of the machine. These are all facts which 
contribute to continuous and satisfactory service, with the 
least possible adjustment and attention. 

As a matter of fact, compounding the air cylinders transfers 
so much of the load from the later to the earlier part of the 
stroke that the maximum terminal stress on bearings is reduced 
fully 45 per cent over those in single stage compression; in the 
above case, from 3140 " ton minutes " to 1727, obviously a much 
easier proposition, mechanically. Misled by this point, it 
has been common to reduce the weight and size of bearings 
accordingly, the mistake being evident, however, when it is 
remembered that the stoppage of circulating water in the cooler 
at once raises the load on the low pressure piston; while a broken 
or damaged outlet valve on the high pressure cylinder may 
at any moment throw the same load on all parts as with a single 
cylinder machine. 

The more equable distribution of the load throughout the 
stroke in compound compression, just noted, also aids in secur- 
ing a higher economy in steam consumption at the other end 
of the machine; for it makes possible an earlier cut-off in the 
steam cylinder and a consequently greater steam expansion, 
with its attendant saving — late cut-offs not being so necessary 
to prevent " centering." Multi-stage compression with effective 
intercoolers between stages also permits a higher piston speed, 
in itself a factor in steam economy by reducing the leakage 
and condensation in the steam end. 

The air remaining in the clearance space between piston and 
head at the end of the stroke must be expanded on the return 
stroke to atmospheric pressure before free air can enter through 
the inlet valves. Evidently the higher the pressure in this clear- 
ance space, the greater this expanded volume and the lower the 
intake efficiency of the cylinder. In single stage compression 



244 SUBWAYS AND TUNNELS OF NEW YORK 

clearance pressure in each cylinder is terminal pressure in that 
cylinder. But this terminal pressure in the intake cylinder 
of a compound is low, usually not over 25 pounds when the 
final working pressure is 100 pounds. The volumetric efficiency 
of compound compression cylinders is higher for this reason, 
the clearance in the low pressure cylinder only being in 
question. 

Another condition conducive to high volumetric efficiency 
resulting from compound compression is the fact that terminal 
pressures, and consequently terminal temperatures, are lower 
than in single-stage cylinders. The cylinder walls and more 
particularly the heads, with the valves and ports which may 
be in them, are therefore kept much cooler and the entering air 
is not so much heated by contact with these parts. A third 
clement entering into the question of capacity is the reduced 
leakage in stage compression cylinders, through valves and past 
piston and rods, with the incidental loss of power. It is evi- 
dent that the higher the pressure the greater the liability to 
leakage; and the smaller range of partly balanced pressures 
In multi-stage cylinders reduces this loss. 

One of the greatest difficulties hitherto encountered in 
air power transmission has been the freezing of the moisture 
in the air, either in the pipe line or at the exhaust ports of the 
air motors. One of the great advantages of the subdivision of 
compression into several stages lies in the opportunity it affords 
for cooling the compressed air at intermediate stages to a tem- 
perature at which its moisture will be precipitated. Of course, 
practically all of this condensation occurs in the inter- and 
aitercoolers; and herein appears the necessity for a design 
which will pass the air at low velocity with full opportunity for 
cooling on the water tubes. The moisture in suspension is 
withdrawn through the drain pipe. It is needless to say that 
unless some provision is made for arresting and withdrawing 
the condensed water from the intercooler, the value of the latter 
as an air drier is lost; for the moisture is carried over into the 
compression cylinders, producing a condition of cutting and 
leakage in valves and rings, and finally working out into the 



APPENDIX F 245 

pipe line. Aftercoolers are in some instances as important as 
intercoolers in removing moisture. 

If air be compressed in a single cylinder from atmospheric 
pressure and temperature of 60 degrees Fahrenheit to a final 
pressure of 100 pounds, the maximum temperature attained 
may be 484 degrees Fahrenheit. This temperature is man- 
ifestly destructive to common lubricants and oils of ordinary 
quality are burned into a solid, gritty, coke-like or gummy 
substance which gives the very reverse of proper lubrication, 
unless proper jacketing devices are employed to keep the parts 
cold. This deposit, moreover, collecting in ports and valves, 
may so obstruct and clog them as to cause leakage and throw 
an added load on the compressor. If, however, this same 
volume of air be compressed in the first cylinder to a pressure 
of 25 pounds, the highest temperature which can be reached 
is only 233 degrees, a heat which will not leave a deposit or 
destroy the lubricating qualities of good oils such as should be 
used in compressor work. This air, passing through the inter- 
cooler, will be brought back to about the original temperature 
of 60 degrees and compressed (in a 2 -stage compressor) from 
25 to 100 pounds in the second cylinder. Here the maximum 
temperature attained will be but little (if any) in excess of that 
in the first cylinder, since the heat of compression is a function 
of the number of compressions and is almost wholly independent 
of the initial pressure. In multi-stage compressors, therefore, 
the conditions of temperature are seen to be most conducive 
to thorough lubrication of pistons and valves, tending toward 
durability and tightness of working parts, with long life and high. 
efficiency of the machine. 

The advantages of compound air compression have gradually- 
forced themselves upon the attention of pneumatic engineers.. 
Not many years ago, when pressures were lower, the majority 
of compressors were single-stage machines. But with the 
growing tendency toward higher pressures, and an under- 
standing of needed economies, compound compressors came into 
greater prominence; and of late much the larger percentage of 
installations have been machines of this style. 



246 SUBWAYS AND TUNNELS OF NEW YORK 

But it will not do to reason that a compound compressor, 
simply as a compound, is more economical than a high-class 
simple machine, for such is not the case. On the contrary, 
only compounds of the highest class are advantageous or deserve 
any consideration from an economical standpoint. 

The gains depend, not simply upon stage compression and 
effective cooling, but also upon correct design throughout the 
machine and a consistent attention to every detail. 

Every condition which may possibly affect the air from 
intake to discharge must be properly considered and provided 
for. Some of these defects which may offset compression 
economy have been noted from time to time throughout the 
preceding discussion. But their importance merits a repetition 
here; a weak structure and small bearings (based on a mistaken 
idea of reduced stresses) with no provision for unexpected con- 
tingencies, resulting in excessive friction losses; multiplicity 
of wearing parts, absorbing a large portion of the power theoret- 
ically saved; heated and restricted air passages, inefficient 
valves, neglect of proper jacket and head cooling; frugal and 
ineffective inter coolers ; poor workmanship, resulting in leakage 
losses. Not only may these defects largely offset the saving 
by compression in stages, but it is a fact that compounds new 
on the market may require more power per cubic foot of air 
compressed than well-designed, high-class, simple compressors 
of equivalent capacity. 

The term " compound " or " 2 -stage " as applied to air 
compressors should properly stand for superior economy. The 
buyer of a compound rightfully expects a saving by its use. 
But poor practice may prove the undoing of the best theory. 
That compressor only is a commercial and economical success 
which embodies a sound theory in a mechanical structure cor- 
rectly designed, built by skilled and careful workmen, and so 
simple as to be readily understood, handled and maintained 
by mechanics of average intelligence. — Lucius I. Wightman, in 
"Power," January, iqo6. 

Altitude Compression. The height of the atmosphere 
surrounding the earth has been variously estimated to extend 



APPENDIX F 247 

from 50 to 20,000 miles, and since air has weight it exerts 
upon surrounding objects a pressure of the air column above 
the object. 

Being very elastic its weight will cause it to have a variable 
density throughout its height and exert varying pressures at 
different altitudes. At the sea level an atmospheric column 
balances a column of mercury 30 inches high and of equal area, 
which corresponds to a pressure of 14.7 pounds per square inch. 
The variation in pressure for different elevations has been 
determined by barometric observations and is given in the 
table following, from which it will be noted that the atmos- 
pheric pressure decreases with increasing height, and as a 
consequence one pound of air occupies a greater volume at 
an altitude than at the sea level (at the same temperature); 
or a cubic foot of air weighs less at a higher altitude than at a 
lower one. 

In descending the shaft of a mine the contrary effect is 
noticed, but in a mine or any level below the sea increase in 
density is counterbalanced by increase in temperature as we 
approach the center of the earth. The temperature of the 
atmosphere also changes with increasing altitude, but is 
not always uniform for any two places at the same eleva- 
tion. 

The volumetric efficiency of an air compressor, expressed 
in terms of free air, is the same at all altitudes (for the displace- 
ment in a given size of cylinder is the same) ; but the volumetric 
efficiency, expressed in terms of compressed air at a given pres- 
sure, decreases as the altitude increases; for the quantity of 
air taken into a given cylinder per stroke being less dense at an 
altitude (due to lower initial or atmospheric pressure) it will 
be compressed into a smaller space for a given terminal pressure. 

To cite an example : 

300 cubic feet of air, at atmospheric pressure of 14.7 pounds, 
compressed to 80 pounds gage, will represent a volume of 

14.7 

^00 X = 46.^ cubic feet. 

^ 947 

If the atmospheric pressure was 10.10 pounds in the above 



248 SUBWAYS AND TUNNELS OF NEW YORK 

IO.IO 

example, then the volume delivered would be 300 X =33. 50 

r ' ° 90.10 °° 

cubic feet; or the volumetric efficiency of a compressor per- 
forming the above work at an altitude of 10,000 feet would be 
but 72 per cent of what it would be at the sea level. 

In order, therefore, that an air compressor may deliver 
at an altitude a volume of compressed air per stroke equal to 
that which it would deliver at sea level, the intake cylinder of 
the altitude compressor must be proportionately larger than 
that of the compressor at sea level. 

Less power is required at an altitude than at sea level to 
compress the free air, taken in by a compressor of a given size, 
to the same terminal pressure (as shown in table following); 
but in order to compress a quantity of air at an altitude which 
is to be equivalent in effect to air at sea level, more power is 
required, because the reduction in power is not proportionate 
to the increase in volume necessary. 

Example : 

To compress 100 cubic feet of free air, at atmospheric pres- 
sure of 14.7 pounds, to 80 pounds gage, requires 17.75 indicated 
horse-power. 

To compress 100 cubic feet of free air, at atmospheric pressure 
of 10.10 pounds, to 80 pounds gage, requires 15.25 indicated 
horse-power. 

But the equivalent volume of 100 cubic feet of free air at 

100 
an atmospheric pressure of 14.7 pounds is — = 139 cubic feet 

.72 

at an atmospheric pressure of 10.10 pounds; and 139 X. 1525 = 

21.2 indicated horse-power; or (for the conditions assumed 

here) 3.45 indicated horse-power more are required at 10,000 

feet altitude to produce the same effect as at sea level. 

The net efficiency of a compressed air plant depends upon 
the type of compressor and engine or motor using the air, the 
working pressure and initial temperature, and whether the air 
is used expansively or at full stroke. 

Most compressed air engines or motors (such as rock drills, 
pumps and hoists), working at an altitude, use the air at full 



APPENDIX F 



249 



stroke; in the following table the volumetric efficiencies, at 
different altitudes, of an air compressor supplying such engines 
with air at full stroke are given. 



RELATIVE VOLUMETRIC EFFICIENCIES AND DIFFERENCES IN 
WORK DONE IN COMPRESSING AIR AT DIFFERENT ELEVATIONS 
COMPARED WITH CONDITIONS AT SEA LEVEL 



"35 
> 
o 


Atmospheric 
Pressure. 


Volume (Cubic Feet) of 1 
Pound of Air (at 6o° F.) 

under Corresponding 
Pressure of Atmosphere. 


Percentage of Increase in 

Volume per Pound of Air 

Temperature 6o° F. 


netric 

Com- 
: under 
unds — 


is 

0°o 


Percentage of Decrease in 
Power in an Air Compressor 
of a Given Capacity, De- 
livering Air at 80 Pounds 
Pressure. 


Work 
ess a 
ivalent 
1 Level 
sure. 


rt 
CO . 

■8.a 

0) 

X) 

3 
< 


u 

3 
«- O 
V u 

■P 0) 

S S 

s-s 



c 

h- 1 


u 

a 

3 

O* 

•d 
c 

3 


ft 


Percentage of Volur 
Efficiency of an Air 
pressor Delivering Aii 
a Pressure of 80 Po 
referred to Sea Level 
tions (Temperature 6 


Percentage of Extra 

Required to Compi 

Quantity of Air Equ 

in Effect to Air at Se; 

to 80 Pounds Pres: 


O 


30.00 


14.7 


13-14 




IOO. O 


0.0 


O.O 


500 


29-45 


14-45 


I3-36 


1-7 


98 


5 


O.38 


1-5 


IOOO 


28.90 


14.12 


13.66 


4.0 


96 


5 


1.38 


2-5 


I500 


28.35 


13.92 


13-85 


5-4 


95 





2.05 


3-o 


2000 


27.78 


13.61 


14.19 


8.0 


93 


5 


2-45 


4.2 


3000 


26.75 


13.10 


14.72 


12.0 


90 


5 


4.02 


6.1 


4000 


25-75 


12.61 


I5-3I 


16.5 


87 


5 


5-27 


8-5 


5000 


24.78 


12.15 


15-88 


20.8 


84 


7 


7.04 


10. 


6000 


23.86 


n-75 


16.41 


24.9 


82 





8.41 


11 .2 


7000 


22.97 


11 .27 


i7-i5 


30.6 


79 


5 


9.70 


14.0 


80OO 


22. 10 


10.85 


17.78 


35-4 


77 





11.05 


15-5 


9OOO 


21.30 


10.45 


18.50 


41 .0 


74 


5 


12.80 


17-3 


IO OOO 


20.60 


10.10 


19. 10 


45-5 


72 


2 


14.00 


19-5 



In designing an air compressor for a high altitude, the above 
factors have to be taken into account; in addition to these 
the influence of a lower back pressure in the steam cylinder 
will have to be considered in the proportion of cylinders. Again, 
a compound air compressor designed for an altitude must have 
a higher ratio of cylinder diameters, so as to divide the work 
equally. 

Conditions of Air Cylinder Lubrication. The fires which 
sometimes occur in air compressor cylinders are due to the 
lubricating oil, the only combustible present. Inferior oils 
cause explosions by reason of the large amount of carbon and 



250 SUBWAYS AND TUNNELS OF NEW YORK 

foreign substances they contain, but they are not the only 
oils responsible for these explosions. The conditions peculiar 
to a given machine may facilitate or retard combustion. For 
instance, in a chemical works, a copper or coal mine, foreign 
substances in the atmosphere may furnish something to feed the 
fire caused by combustion of the residual carbon. Most oxida- 
tion in all cases takes place at the junction between cylinder 
and discharge pipe. Continual oxidation so reduces the size 
of the pipe that more air is compressed in the cylinder than can 
pass through the pipe. Increased friction and compression 
cause an abnormal degree of heat in the cylinder, and trouble 
from fire is experienced. In all cases an oil should be used which 
causes the least oxidation possible, its flash-point being as high 
as consistent with good lubricating qualities. Ignition in the 
compressed air delivery pipe is not uncommon, as shown by the 
explosion of two air receivers during the construction of the 
New York aqueduct; in one case the engine-room was destroyed 
by the resultant fire. The explosion was caused by the use of 
an oil of very low flash-point. This ignition has extended in 
some cases to the air receiver, and in one instance the flames 
were carried down into the mine by the compressed air. In 
some cases the pressure recorded by the gage has not been so 
high as that equivalent to the flash-point temperature of the oil. 
There must, however, have been an increase in temperature, 
and this is due to a momentary increase caused by the con- 
stricted air passages being choked by the deposited carbon. 
Trouble is increased by using too much oil, either of good or 
bad quality. This source of trouble is rather common, for 
many engineers have an idea that an air cylinder requires as 
much oil as a steam cylinder. Consequently deposition of 
carbon goes on at a very rapid rate. The carbon deposit can 
be removed by kerosene. Care should, however, be exercised 
in the use of that same, for its flash-point is about 120 degrees 
Fahrenheit, and its careless introduction through the inlet valve 
has accounted for many explosions. Engineering Times, 
London. 



APPENDIX G 
SOME AIR LIFT DATA 

Air lifts are used to quite an extent in this section (Los 
Angeles, Cal.) for raising water and oil, in some cases oper- 
ating in oil wells 2000 feet deep or more. In many cases the 
cost of installation is moderate, and in all cases the cost of 
maintenance is very low; and air lifts, with compressors of any 
reasonable size, can be operated more economically than ordinary 
deep- well pumps. There are many situations where they are 
really the most economical appliances that can be used. 

It is necessary, however, to have a proper amount of sub- 
mergence to get economical operation. The exact amount 
of submergence for best work varies a little with the lift and 
quantity of water handled. Ordinarily, for lifts of 40 feet or 
less I would recommend about two and one-half to one — that is, 
two and one-half times the amount of pipe below the surface of 
the water in the well when pumping the maximum quantity, 
to the lift above this level. With lifts of from 50 to 80 feet, 
two to one generally gives good results. On deeper lifts one 
and one-half to one is frequently used. There are situations 
where sufficient submergence cannot possibly be obtained, 
and while the pumps may be operated with considerably less 
submergence, it ' generally increases the cost of pumping some- 
what. 

The quantity of air required depends somewhat on the size 
of the installation, the proper proportioning of the pipes, flow 
of water in the wells, etc., and it is impossible to give the exact 
quantity, as it is very seldom that two wells will work exactly 
alike. 

I give herewith a table showing the approximate quantity 
of air required and working pressure for all ordinary cases, but 

251 



252 



SUBWAYS AND TUNNELS OF NEW YORK 



know of a number of installations that are operated successfully 
with from 15 to 20 per cent less air than is shown in this table, 
and a few installations that use more. 

APPROXIMATE CUBIC FEET OF FREE AIR AND WORKING PRESSURE 
REQUIRED TO RAISE ONE GALLON OF WATER BY AN AIR LIFT. 



RATIO OF SUBMERGENCE TO LIFT. 





1 to 1. 


i§ to 1. 


2 to 1. 


2\ to I. 


Lift in 
Feet. 


Free Air, 
Cubic 
Feet. 


Working 
Press- 
ure, 
Pounds. 


Free Air, 
Cubic 
Feet. 


Working 
Press- 
ure, 
Pounds. 


Free Air, 
Cubic 
Feet. 


Working 
Press- 
ure, 
Pounds. 


Free Air, 
Cubic 
Feet. 


Working 
Press- 
ure, 
Pounds. 


20 

30 

40 

50 

60 

80 

IOO 

I20 

140 

160 

180 

200 


O.428 

O.47 

O.508 

0.546 

0.582 

0.653 

O.72 

O.785 

O.847 

O.907 

O.965 

1 .022 


9 

i3l 

18 

22j 

27 

36 

45 
54 
63 
72 
81 
90 


O.31 

0.35 

O.387 

O.422 

0-457 
O.522 

0.585 
O.642 
O.697 

0.755 

O.81 

O.862 


I3l 

20 

27 

34 

40I 

54 

67* 

81 

94? 
108 

I2l£ 

135 


O.252 
O. 29 

O.325 

O.36 

O.392 

0-455 
O.512 
O.567 
0.622 
O.675 
0.725 
0-775 


18 

27 

36 

45 

54 

72 

90 

108 

126 

144 

162 

180 


O.217 
0.255 
O.287 
0.32 

0.35 

0.41 

O.465 

0.52 

O.572 

0.624 

0.672 

0.72 


22j 

34 

45 

56 

67* 

90 
112^ 
135 
157^ 
180 
202 
225 



In selecting a compressor it is well to allow a surplus over 
the amount given in the table, as it cannot always be known 
before testing how much the water in the wells will fall when 
being pumped; and while some of the better makes of the 
larger sizes of compressors will give a volumetric efficiency of 
over 90 per cent, there are some of the smaller sizes of com- 
pressors, with poppet inlet valves, that are deficient in inlet 
valve area, and some of them will not deliver 60 per cent of the 
amount of air that is shown by piston displacement when running 
at full speed. This, of course, varies with the inlet valve area 
and speed. 

The size of air pipe is not very important, providing it 
is large enough to carry the air without undue friction, and the 
working pressure given is based on there being very little fric- 
tion. 



APPENDIX G 253 

The size of the pipe in which the water is lifted to the sur- 
face is, however, quite important, as there must be a fairly 
high velocity to work properly, and it is better to err in having 
the pipe a little too small than too large. The best work is 
generally obtained with a flow of from 12 to 18 gallons per 
square inch of section. Smaller pipes will not stand quite 
so high a velocity as larger sizes. 

The arrangement of the air nozzles at the bottom is not 
a matter of very great importance, provided, of course, the air 
pipe is somewhat above the bottom of the water pipe. There 
are a number of different arrangements that give good results. 

In some cases, where it is desired to deliver the water at 
some distance away from and above the well, where sufficient 
submergence cannot be obtained, air displacement pumps are 
used; that is, a cylinder or chamber is lowered into the well 
below the water line and provided with valves somewhat similar 
to pump' cylinders, being alternately filled and emptied with 
air under pressure. What is known as the " dense air " system, 
by which the air is returned to the compressor under consider- 
able pressure, increases the economy of the compressor and 
makes a satisfactory and very economically operated pumping 
plant. 

Direct-acting deep- well steam pumps are generally very 
wasteful in the use of steam, and very seldom are any more 
economical to operate than a good air-lift system, properly 
installed. All kinds of deep-well pumps, having a long line of 
rods, generally are quite expensive to maintain, to say nothing 
of the trouble and time lost in pulling and replacing rods and 
buckets. They are good things to keep away from wherever 
it is possible, particularly where any considerable quantity of 
water is required from deep wells. However, when operated 
at very slow speeds, and large capacity is not required, their 
use is sometimes admissible. Power, New York. 

Cost of Pumping with the Air Lift. This question is usually 
asked without giving several items which largely determine 
the answer. Thus, coal at $2.00 is one thing, at $4.00, another. 
Again, some wells are nearby, and in other plants the pipe invest- 



254 SUBWAYS AND TUNNELS OF NEW YORK 

ment is greater because of scattered wells. Speaking gen- 
erally, the average cost per thousand gallons pumped depends 
on the size of plant and height of lift. In a 4,000,000 gallon 
plant, with a 50-foot lift, it is about one- third cent per 1000 
gallons. In a larger plant, with a 35-foot lift, with coal at 
$2.00, it is about one and one-half mills. In another case, 
where the lift is 75 feet and the capacity one and one- third 
million gallons, the cost is one cent per 1000 gallons, coal cost- 
ing $2.00. In a plant pumping 3,000,000 gallons 75 feet high, 
the cost is 4.5 cents, and where the lift is 50 feet, 3.5 cents. 
In Pennsylvania, a plant giving 175 gallons per minute at 75- 
foot lift, costs one and one-third cents per 1000 gallons. In a 
proposed municipal plant, 100,000,000 gallons per twenty- 
four hours, 50-foot lift, and with coal at $1.50 a ton, the cost 
figured 1 mill per 1000 gallons, including all fixed and operating 
expenses. In another case, involving the handling of about 
15,000,000 gallons of water 30 feet high every twenty-four 
hours, using compound condensing compressors and with 
coal at $2.00 per ton, other figures being estimated on a very 
generous basis, the cost nets about $2.50 per 1,000,000 gallons, 
or about two and one-half mills per 1000 gallons. These figures 
cover fuel, oil, labor, sinking fund, interest and taxes. 

In many cases the introduction of the air lift may be effected 
at little expense, often involving the purchase only of an air 
compressor, a receiver and a small amount of pipe; but the 
following is estimated on a basis which will cover the greatest 
amount of expense likely to be incurred, with a view of showing 
particularly that the interest and depreciation charges under 
the most extreme conditions are not likely to develop into 
formidable figures. The following is a list of the complete 
equipment for an air lift plant to raise 1,500,000 gallons per 
twenty hours, or 1250 gallons per minute. Total lift, 75 feet; 
air compressor, complete, ready for foundation and piping; 
air receiver; boiler, 85 h.p., with feed pumps, etc., bricked up 
and ready for use, including building and value of ground so 
occupied; tank, 19,000 gallons capacity, including suitable 
timber framework to bring tank 75 feet above water level; two 



APPENDIX G 255 

1 2-inch wells, each 135 feet deep, cased; casing, 450 feet 7f-inch 
light pipe; air pipe, 500 feet of 3-inch air pipe in wells; air 
pipe, 1000 feet of 4-inch air line from receiver to wells; water 
pipe, 1250 feet of 12, 10 and 8-inch cast-iron distributing main, 
leaded joints, from tank to works, laid below frost (air line 
laid in same trench); all other pipe and fittings; compressor, 
receiver and tank foundations, laid in cement ; special automatic 
governing mechanism; total estimated cost of complete plant, 
ready to run, as above, $8750. This is intended to include 
everything which may be considered as a legitimate expense in 
this connection. In many cases the buildings, boilers, tanks, 
wells, pipe lines, ground space, and other items do not represent 
a present expense, being already on the ground. 

We may estimate the cost of operation as follows : Engineer, 
double shift, at $2.25 per day, $4.50, one-fifth time chargeable 
to pumping plant, per day, $0.90; fireman, double shift, at 
$1.75 per day, $3.50, on the basis of one man required for each 
250 h.p. of boiler, for 85 h.p. per day, $1.19; fuel, 85 h.p., 
twenty hours, say four and one-quarter tons, at $2.00 per ton, 
per day, $8.50; oil, waste and sundries, say, 60 cents; interest 
on investment of $8750 at 5 per cent, figuring eleven 25- 
day months, or 275 working days per year, per day, $1.91; 
deterioration, covering sinking fund, repairs, etc., providing 
for renewal of complete plant every ten years, same basis as 
interest but 10 per cent, per day, $3.18; insurance and taxes 
at 1 per cent, as above, per day, thirty- two cents; total estimated 
cost of pumping 1,500,000 gallons per day, 75 feet high, under 
the above conditions, $16.60. Cost of each 1000 gallons 
$16. 60-M 500 = $0.01107. Engineering Record. 



APPENDIX H 

COMPRESSED AIR LOCOMOTIVES 

Two Compressed Air Mine Locomotives. The halftones here- 
with show two interesting compressed air locomotives recently 
built for mine service by the Baldwin Locomotive Works. Both 
these engines are of the four-coupled type, but they differ from 
each other more than the half tones suggest, both in size and in 
many constructive details. 

The locomotive for the Lehigh Valley Coal Company is 
built within a width limit of 5 feet 6 inches and a height limit of 
5 feet 7 inches, the length over the bumpers being 14 feet. The 
frames are of forged iron, and they have a slab section ahead 
of the leading driving pedestals. This construction provides 
a ready means for supporting the cylinders, which are placed 
between the frames and are securely bolted to them. The 
cylinders are set on an incline of one in ten, so that the main 
rods will clear the leading axle. The driving axle, of course, 
has two cranks inside and is a steel forging made in a single 
piece. There are two similar air tanks with a combined capacity 
of 95 cubic feet. Air is stored in these tanks at an initial pres- 
cure of 800 pounds, and a reducer keeps an auxiliary reservoir 
constantly charged to a working pressure of 140 pounds. Safety 
valves are provided for both the main and the auxiliary reservoirs 
at their respective pressures. The equipment includes air 
brakes for all the wheels, also four sand-boxes with spouts to 
all the wheels. The principal dimensions are as follows: 

Gage, 4 feet. 

Cylinder, 8 by 12 inches. 
Driving-wheels, 28 inches diameter. 
Wheel-base, 4 feet. 

256 



APPENDIX H 



257 



Tractive force, 3260 pounds. 
Weight, 18,000 pounds. 

The locomotive for the Gilson Asphaltum Company, Mack, 
Col., may be said to be about one-half the size or capacity 



" "Am i-iinnft ' 

HA ^wiSc ^B 


Tn Br 9 1 nfiHFi i 


1 


■1 «L#3o(}l Ik 


^^H ^B' ' '"*U ^R^lKdv' ^Mti. /%*». ~^m£m 


11 JEF^^w# 


IIIElw 


If ^1 1^3 


Bi ililCTf 


| 






Igiijf 





of the preceding. It is lighter and more compact. In the 
mine where this locomotive is used the air is charged with 
gilsonite or asphalt dust, rendering it dangerously explosive, 
so that compressed air haulage was adopted as a safety pre- 
caution independently of other considerations. The narrow- 



258 



SUBWAYS AND TUNNELS OF NEW YORK 



ness of the gage permitted only a single air storage tank which 
has a capacity of 39 cubic feet. The charging pressure is 
800 pounds and the working pressure of the auxiliary tank 
140 pounds. The frames are of plate steel, supported on coiled 




springs. The air tank rests directly on the frames, the points 
of support being over the springs. The cylinders are placed 
outside the frames in a horizontal position. The function of 
the heat radiating rings cast around the cylinders is in this case 
reversed, as the cylinders cool in working and the rings absorb 



APPENDIX H 



259 



heat from the atmosphere and help maintain the temperature 
at a workable point within. 

This engine is provided with a sand-box on each side, and 
sand can be blown under either front or back wheels. Air- 
brake equipment also is provided with shoes on all the wheels. 
The auxiliary air tank is placed on the left side and is fitted with 
a safety valve, as is also the main tank. The nozzle and valve 
for recharging are seen on the side. The principal dimensions 
of this engine are as follows: 

Gage, 2 feet 6 inches. 
Cylinders, 5J by 10 inches. 
Driving-wheels, 20 inches diameter. 
Wheel base, 3 feet 6 inches. 
Weight, 8650 pounds. 
Tractive force, 1800 pounds. 

From Compressed Air Magazine. 

German Compressed Air Mine Locomotives. We illustrate 
on these pages a type of compressed air locomotive introduced 
by the Berliner Maschinenbau- 
Actiengesellschaft, Figs. 1 and 
2 being end and side outline ele- 
vations respectively, not to the 
same scale, and the half tone, 
Fig. 3, showing a locomotive in 
actual service and stopped at 
a charging station for a fresh 
supply of air. 

The standard pattern of the 
machine is of 8 to 12 nominal 
horse-power, but is capable of 
working up to 24 h. p. as a maxi- 
mum, and, under ordinary condi- 
tions of gradient, will haul about 
forty full tubs, each with a net 
load of 11 cwts., at a speed of 
five and one-half miles per hour. It will run a distance of about 




260 



SUBWAYS AND TUNNELS OF NEW YORK 



1600 to 3200 yards with a single charge of air, the pressure 
sinking from about 750 pounds per square inch to 150 pounds. 




Fig. 2. 



Even under the latter conditions, however, the engine can run 
empty for another 1500 to 2000 yards, so that the driver can 



■ 


n 






-Am M>?£! 


• - J> 




" ■ 

f \ 


w- ' 



Fig. 3. 



easily reach a recharging station should the locomotive be 
unable to haul the train at any point of its course. 



APPENDIX H 261 

The dimensions of the locomotive are as follows: Total 
length over buffers, 13 feet; maximum height above the rails, 
5 feet; maximum width, 3 feet; wheel-base, 40 inches. With 
these dimensions curves of 33 feet radius can be negotiated 
without difficulty. The effective adhesion weight of the loco- 
motive is about five and one-half tons, so that it is capable of 
exerting considerable tractive force, even on greasy rails, without 
slipping. 

As shown in Figs. 1 and 2, the locomotive consists of the 
main air receiver, a, auxiliary receiver, b, the motion, c, and the 
frame, d, with the requisite valves and fittings, including safety 
valves and pressure gages for both air vessels, a reducing 
valve, signal bell, sanding appliances, powerful brake, lamp, 
etc. The driver's seat is above the driving cylinders, and 
all parts of the motion are easy of access. The air supply is 
compressed to n 25 or 1500 pounds per square inch, and stored 
in reservoirs. These are connected by air mains with charging 
reservoirs (Fig. 3), situated at a convenient place for recharging. 
This latter operation is effected in a very short time; in fact, 
it is claimed that one to one and one-half minutes will be suf- 
ficient, on account of the high pressure in the recharging cylin- 
ders. The difference between the pressure of 750 pounds in the 
locomotive air cylinder and 1500 pounds in the compressor 
equalizes the work of the latter, so that it can be kept running 
continuously, even when the loads to be hauled are subjected 
to considerable fluctuation. In the event of the compressor 
supplying more air than is being consumed by the locomotives, 
an automatic valve on the former opens and allows the com- 
pressor to run empty until the pressure in the reservoirs has 
fallen below the limit of 1500 pounds. 

The working pressure in the engine cylinders is lowered to 
150 pounds by a reducing valve of special design, the air being 
passed through an auxiliary air chamber. An early cut-off 
permits the expansive power of the air to be fully utilized. 

From Compressed Air Magazine. 



APPENDIX I 



ROCK DRILLS AND MOUNTINGS 



The percussive rock drill, as distinguished from all other 
types, is an American invention, the first practical patents 
having been taken out by J. J. Couch, of Philadelphia, in 1849. 
Couch was assisted in building this drill by Joseph W. Fowle, 
later of Boston, their experiments being carried on during the 
year 1848. The Couch drill was a crank-and-fly- wheel machine, 




Rand " Little Giant " Tappet Valve Rock Drill with Plain Slide Valve. 

and its application to practical work was therefore limited to 
surface hole drilling. 

In 1848 Couch and Fowle separated, Fowle filing a caveat 
in 1849. This caveat describes the type of successful power 
rock drill used to-day. The chief point was that Fowle first 
showed a drill where the cutting tool is attached directly to the 
piston or to the cross-head connected with the piston. This 
important invention was described by William Fowle, in his 
testimony before the Massachusetts Legislative Committee in 
the contest with Burleigh in 1874, as follows: 

" My first idea of ever driving a rock drill by direct action 
came about in this way: I was sitting in my office one day, 

262 



APPENDIX I 



263 



after my business had failed, and happening to take up an old 
steam cylinder, I unconsciously put it in my mouth and blew 
the rod in and out, using it to drive in some tacks with which 
a few circulars were fastened to the walls." 

The nearest approach to rock drill inventions abroad was 
in the German work of Schumann in 1854. Fowle being without 
means, but a genius in the true sense, his inventions remained 
in obscurity until Charles Burleigh purchased his patents and 
produced the Burleigh drill, about the year 1866. This drill 
was used in the Hoosac Tunnel in 1867. 

Following these inventions came Haupt, De Volson Wood, 
and Simon Ingersoll, and after these men Sergeant, Waring and 




Rand " Little Giant " Tappet Valve Rock Drill with Balanced Valve. 



Githens, Githens being the inventor of the Rand drill. The 
Ingersoll drill was invented in 187 1.* 

The percussive rock drill as used to-day may be divided 
generally into three types, distinguished by the operation of 
the valve. 

The three types are : where the valves are operated by tappets 
or rockers, by steam or air, or a combination of the tappet and 
air- thrown system. The three types are exemplified by the 
Rand, the Ingersoll, and the Sergeant drills, respectively. 

The valve mechanism of the Rand drill is made up of three 
pieces — the valve, the rocker, and the rocker pin. The rocker, 
turning on the rocker pin, is in contact with the piston at one 

* From " The History of the Rock Drill," by W. L. Saunders. 



264 



SUBWAYS AND TUNNELS OF NEW YORK 



point and projects into the valve in its upper arm, which ends 
in a globular form. When the piston moves, a curved surface 
slides under a rocker contact, pushing the rocker upward and 
swinging the valve in the same direction as the piston moves. 
On the reverse travel of the piston this series of movements is 
exactly reversed. 

The distinguishing characteristic of this drill is the positive 
character of its valve movement. There is no lost motion, 
no incomplete travel, no fluttering of the valve, no uncertainty 
in the machine movement. When steam or air is admitted 
to the cylinder the piston must move; and when the piston 
moves, the valve must be thrown. 




" New Ingersoll " Air-thrown Valve Rock Drill. 



While the tappet movement is adapted to the use of either 
steam or air, it is as a steam-driven machine that the tappet 
drill shows its peculiar superiority. Steam pressure may not 
be high and the steam may be " wet." Under such conditions 
the " steam thrown " valve is slow in action and labors under 
the burden of releasing water of condensation. The tappet 
valve, however, is superior to these difficulties encountered 
with the use of steam. 

The Ingersoll drill has an independent air-thrown valve, 
the action or which is controlled by the movement of the piston. 
It has the variable stroke so necessary in working in caving, 
seamy or broken ground; while its quick return " muds " 
the hole well. The blow is practically uncushioned. With 
compressed air or with reasonably dry steam this drill will 
give excellent results in any ordinary material to which per- 
cussion drills are suited. 



APPENDIX I 



265 



In certain classes of work there are several positive advan- 
tages in the " tappet " principle as applied to rock drill valve 
movements. But the mechanical tappet, struck hundreds of 
blows per minute and millions of blows per month by a heavy 
piston moving at high velocity, demands qualities of design and 
material possible of attainment only to a long experience. Long 
practice has demonstrated that in the majority of cases the " inde- 
pendent" valve action gives a better machine, using less air or 
steam per foot of hole drilled than any other pattern. Yet the 
positive quality of the tappet movement holds an important 
place in many classes of work. 




" Sergeant " Auxiliary Valve Rock Drill. 

The " Sergeant " drill is a successful combination of the 
" independent " air- thrown valve of spool type with an improved 
modification of the tappet action. It retains certain advantages, 
while avoiding defects, of both valve movements. The valve 
movement is one in which the strains, shocks and jars to which 
the tappet or rocker is subjected are transferred from the main 
valve, with its vital and delicate functions, to a smaller aux- 
iliary valve weighing only a few ounces, specially designed to 
withstand this service to best advantage, and cheaply replaced 
when worn. But the wear upon it is almost imperceptible. 
A valve seat between valve chest and cylinder carries an exten- 
sion fitting into a recess in the latter. In this extension is 
milled an arc-shaped groove or slot in which the light aux- 
iliary valve slides freely. The main valve is of the balanced 
air-thrown spool type, with wearing surfaces ground to a plug 



266 SUBWAYS AND TUNNELS OF NEW YORK 

fit in a reamed valve chest. One end or other of the auxiliary 
valve projects slightly into the cylinder bore and is pushed or 
lifted by the piston in its travel. This movement is perfectly 
free and very short — only enough to uncover a small port which 
releases pressure from one end of the main valve; full pressure 
on the other end then throws this main valve, opening wide 
the main port and admitting full pressure to the piston for the 
return stroke. 

The auxiliary valve is simply a trigger which releases the 
main valve. It is accurately machined from the best tool 
steel, and is hardened. Being very light, its impact cannot 
injure or retard the piston; nor is there any of that crowding 
of the piston against the opposite cylinder wall which has been 
such a fruitful source of trouble in ordinary tappet drills and 
responsible for the rapid wear of rings, pistons and cylinders 
in machines with ordinary unbalanced, hard-moving tappet 
motions. Pressure being on the back of the auxiliary valve, 
continued wear only improves its seating. Its action is quick, 
positive and perfectly free. 

The main valve is accurately ground from hardened tool 
steel and is protected by buffers at the end of its travel; breakage 
is unknown. Being perfectly balanced, it moves freely with 
little wear, and the full port opening is secured almost instantly. 
The combined action of these two valves is such that admission 
and exhaust ports, instantly opened, retain full opening to the 
end of the stroke. There is therefore no cushion pressure to 
retard the stroke and diminish the blow ; and for a given diameter 
of cylinder and a given weight, this is by all odds the most 
powerful drill made. 

The " Sergeant " drill has a wide variation of stroke, secured 
simply by " cranking " the machine forward, without any 
valves or other regulating devices. The blow is absolutely 
dead, and no machine of equal cylinder diameter can match 
it in its effective penetrating quality. The ability of this drill 
to run on a very short stroke is of special advantage in start- 
ing a hole on an oblique surface and in avoiding a glancing 
blow, with consequent breakage of the starter shanks; it also 



APPENDIX I 267 

admits of the hole being quickly started without " funneling " 
or " rifling." This feature is of vital importance under many 
drilling conditions — such as working through seams, in shelly 
or caving material where pebbles fall under the bit, in crevices 
or alternate layers of hard and soft rock, and in many other 
circumstances familiar to drill runners and likely to be encoun- 
tered anywhere. The drill also " muds " or cleans the cuttings 
out of the hole in a most effective manner. 

Another most important advantage of the variable stroke 
of the " Sergeant " drill, and one appealing to the practical man, 
is that it makes possible the use of odd steels which, by wear 
or breakage, have become of uneven length. Some other drills 
cannot use steels differing more than 2 inches from standard 
lengths. Steels shortened as much as 5 inches can be used with 
this drill. This fact allows more leeway in starting the machine 
after changing steels, without moving the setting, wasting time 
in getting an odd steel shortened, or hunting up a steel of the 
right length. Drills of other types are compelled to start on 
practically full stroke. 

Another valuable feature of design in this drill is that the 
valve action is not dependent upon the condition of cylinder, 
piston or rings. It has an absolutely positive and independent 
valve movement. Other types of independent valve machines 
operate well only so long as the piston is a good plug fit in the 
cylinder; and, cylinder walls, piston and rings being inevitably 
subject to wear and consequent leakage, the valve action is 
soon at a serious disadvantage and requires very extensive 
repairs or entire rebuilding. The auxiliary valve, in striking 
contrast to this, will perform its functions perfectly, even with 
a loose piston or with the rings entirely absent from the machine. 
To this exclusive feature of design is largely due the sustained 
capacity of this drill. But it is almost unnecessary to state 
that a tight piston is always advisable in the interest of highest 
efficiency and good air or steam economy. 

Remarkable records have been made in the hardest rock by 
drills of this type; performances just as remarkable have been 
noted in soft and medium rocks — facts leading to the belief 



268 



SUBWAYS AND TUNNELS OF NEW YORK 



that this can be justifiably called an " all-around " drill. For 
rapid tunnel driving and hard service anywhere it is without 
doubt the best machine to-day. It is a rapid and economical 
drill under almost any condition, except where its dead, stunning 
blow loses effect in " springy " or elastic material. The best 
results are always secured with live, active air; but dry steam 
brings out a good performance also. It is a simple, rugged 
machine, and the frequent remark about it is that " any black- 
smith can keep it in good running order." All bolts and threads 




Ingersoll-Rand " Universal " Tripod for Rock Drills. 



are standard; there is nothing " special " about it. In long- 
continued service under the most severe conditions its repairs 
have been found to be less than upon any other model of drill; 
while recent improvements in details have added to its ecomony 
and power. 

Rock Drill Mountings. The essentials of a successful 
tripod are: a flexibility adapting it to rough surfaces, a wide 
and ready adjustment, and a great strength and rigidity in 
service. The " Sergeant " tripod, here illustrated, meets the 
requirements. All adjustments are independent, and a single 
wrench fits all nuts. At all joints a wedge effect is secured 



APPENDIX I 



269 



by the use of cone-shaped clamping surfaces of large area. 
The legs are telescopic and the weights can be adjusted at any 
height. 

In tunnel work, in shaft sinking, in mining, and, to a more 
limited extent, in quarry work, the column or bar has become 
an indispensable form of drill mounting. 
It is simply an extra heavy wrought steel 
tube, carrying at one end a rosette-shaped 
head, and at the other one or two jack 
screws suitably mounted. One or more 
column arms may be mounted and clamped 
on the column, carrying the drills; or, the 
drill may be mounted directly on the 
column. In either case, a safety clamp, 
secured on the column below the column 
arm or drill, prevents the latter from 
falling when the clamp bolts are loosened 
to swing around the column in changing 
steels. Under this general classification 
there are three distinct types, described as 
follows : 

In tunnel work, with a heading or drift 
of 8 or 9 feet, a double-screw column is the 
usual mounting for drills. Each column 
may carry two or more machines, the number 
of the latter required depending upon the 
size of heading and the rate of advance. 
In tunnels 27 feet wide and 24 feet high, Ingersoll-Rand Double- 
with 8-foot headings, it is customary to use Screw Column, 
four drills on columns in the heading and 
two on tripods on the bench. In tunnels 15 feet wide and 18 
feet high, with 8-foot headings, three drills are ordinarily used. 
The double-screw column has two jack screws at the base, 
which give great security and rigidity. The drill on the column 
has a great range of adjustability; it may be shifted sideways 
on the arm, and the arm may be raised or lowered or swung 
completely about the column. 





270 



SUBWAYS AND TUNNELS OF NEW YORK 



The single-screw column or shaft bar is a mounting designed 
for rapid and economical shaft sinking. The various lengths 
of bar accommodate various shaft openings. This device has 
but one jack screw, which is fitted with a patent lock nut, 
giving perfect security against working loose. For shafts 
less than 8 feet across, the bar should carry but one drill. For 

larger shafts, two drills on a bar 
may be used, the latter being 
supported by center legs. The 
arms permit of lengthening 
or shortening, can be swiveled 
to any position, or may be 
swung completely over to drill 
on both sides of the bar. Drills, 
arm and bar may be folded 
compactly together and re- 
moved bodily when a blast is 
to be fired. 

The stoping bar is simply 
a short bar upon which the 
drill is mounted directly with- 
out any column arm. It has 
one jackscrew, secured by a 
lock nut, and is designed for 
stoping work in mines or for 
light drilling in a drift or 
heading. 

Hammer or Plug Drills. 
The hammer drill or " buzzer " 
is undoubtedly playing a most important part in the economi- 
cal working of modern mines. It has passed through a long 
and expensive development period. It is natural that in the 
creation of an entirely new device experience alone can work 
out the best features both of practical design and of prac- 
tical application of the tool. Many designs have failed; and 
while the correct principles were being traced out, much has 
been learned as to the proper field of use of the hammer drill, 




Ingersoll-Rand Double-Screw Column 
with Arm and Saddle for Rock Drill. 



APPENDIX I 



271 



builders and users alike learning its limitations and its possi- 
bilities. 

The standard piston rock drills have no equal in the class 
of work for which they are properly adapted, viz., the drilling 
of comparatively large and deep holes at all angles. But as 
the diameter and depth of hole best suited to move a given amount 
of rock diminish, a point is reached where the economical field 




" Little Giant " Drill on Single-screw Column or Shaft Bar. 



of the standard drill merges into one best covered by the hammer 
drill. The dividing line is reached, in mining work for instance, 
where narrow stopes are encountered, where upraises have to 
be driven, as in the caving system, in underhand stoping, 
where a thin vein must be worked with a minimum breaking 
of waste rock, or wherever small, comparatively shallow holes 
(usually (( up " holes), easy placing of the machine used and 
economical drilling through reduced " dead time " become 
determining factors. This means that as large a proportion 
of the time as possible shall be spent in actual drilling 
rather than in setting up and moving. From the line here 



272 



SUBWAYS AND TUNNELS OF NEW YORK 



defined the field of the hammer drill extends down to the 
drilling of the smallest holes for trimming, pop shots and 
similar work. 

The diameter of the hole has everything to do with the 
question of economical rock drilling. With the hammer drill, 
as with all other classes of rock drills, the drilling speed and 

consequent cost of air and labor, 
and the strains, breakage and en- 
durance of steel and parts are 
greatly affected by the diameter 
of the hole drilled. No attempt 
should be made to drill large holes 
with these small machines, but 
the smallest holes which will break 
the ground should be adhered to, 
as in hand drilling.. . But failure to 
appreciate this simple point is at 
the root of most of the complaints 
of high cost of work with any class 
of rock drills. 

The term " hammer drill " is 
here used as distinguishing those 
light machines in which the steel 
is not attached to and reciprocated 
with the piston, but is struck by 
the hammer or piston, as in hand 
"Imperial "Hand Hammer Drill, drilling. They are usually used 

without any mounting, but are 
handled and directed simply by the operator's hands. It is 
to be noted, however, that there are instances where these 
machines are also used with fixed mountings. This classifica- 
tion includes not only the ordinary hand tool — the original 
type of " plug drill " — but also the telescope air-feed machines 
for "up" holes. 

The hammer drill is rapidly supplanting hand drilling in 
every field purely on the ground of lower cost per foot of hole 
drilled. This type is not for one moment to be considered as a 




4802 



APPENDIX I 



273 



substitute for the standard piston rock drill. Its principal 
application is in the class of work which the larger machine 
never even attempted to handle, for most of the drilling in many 
mines and contract jobs is still done by hand. 








4597 



"Crown" Hand Hammer Drill. 



The hammer drill is extremely simple, having only one, 
or at the most two, moving parts. This means a steady reliabil- 
ity and ease of up-keep, with low repair costs in the best types. 

Requiring but a moment to change steels or start a new 



274 SUBWAYS AND TUNNELS OF NEW YORK 

hole, probably 70 to 90 per cent of the work paid for is applied 
in actual drilling, while with an ordinary piston drill usually 
not more than two thirds and often less than half the time is 
actual drilling time. This is a most important point in work 
where a large number of small, shallow and carefully placed 
holes are required. 

The hammer drill can be used in extremely close quarters — 
places where no piston drill with a fixed mounting could be used, 
or even a hand hammer swung. Wherever a man can go he 
can take a hammer drill with him. It is truly a " handy " 
machine, easily carried anywhere under all conditions. 

The air consumption of hammer drills is about one-half 
that of the smallest piston drill, meaning that a given com- 
pressor plant will run twice as many hammer drills, doing 
probably twice the work, and often more, in certain conditions; 
or, the initial power and plant investment for a hammer drill 
outfit to do a given work, as in prospecting or development, 
need be much less than that required for an equipment of piston 
drills. 

No special skill is required to operate a hammer drill, and 
herein lies one of its greatest advantages. Only a skilled machine 
man can overcome a " fitchered " hole, start a difficult hole, or 
determine the proper feed and stroke, thus getting maximum 
results with the piston drill. But a half day's work will famil- 
iarize any intelligent laborer with a hammer drill. One skilled 
drill man can direct or " point " the holes for half a dozen or 
more hammer drills — a most important item where good men 
are hard to get. 

It is a fact that one hammer drill will average an equivalent 
of six to fifteen hand drillers. Good labor is every year more 
scarce. If ten hammer drills will do the work of one hundred 
men, they are certainly a good investment. With a limited 
force provided with these drills ten times the drilling can be 
done and the footage correspondingly increased, thus getting 
cheap machine results in a short time which would otherwise 
take much longer. 

This advantage goes still farther. Much of the economy 



APPENDIX I 



275 



of blasting depends upon the holes being properly and skillfully 
placed to bring out the maximum quantity of rock with the 
minimum powder charge and with the minimum amount of 




" Crown " Plug Drill with Air Jet for Blowing away Dust. 



undesirable waste rock. It is certainly true that the average 
skill of ten selected hammer drill men will be higher than that 
of a gang of one hundred hand drillers. The importance of this 
point in its bearing on low costs and improved operating con- 
ditions will be appreciated by every contractor. 



276 



SUBWAYS AND TUNNELS OF NEW YORK 



The experience of the most careful users has shown that the 
hammer drill brings about a most important reduction in the 
cost of explosives. The average powder man will load a hole to 
the limit, regardless of whether so much powder is needed or 
not. The small hole made by the hammer drill reduces the 
likelihood of overcharged holes or " over-shooting." 

The hammer drill in the quarry is usually of the plain hand- 




" Imperial" Valveless Telescope Feed Hammer Drill or Stoper. 



tool type, and finds its application in drilling plug-and-feather 
holes, pop holes, block holes and anchor bolt holes. 

In mining and tunneling practice the prevailing type is 
the air-feed hammer with automatic telescope feed, though the 
hand tool has also a limited application. Its work here is 
drilling in upraises, stoping, following narrow, rich veins, 
squaring up, cutting hitches, trimming walls, and the occa- 
sional drilling of " pop " holes and block holes. 

In the coal mine the hammer drill is useful in cutting ditches, 
sumps, etc., levelling floors, taking off rolls or " horse backs," 
taking down roof, taking up floors, brushing entries, cutting 



APPENDIX I 



277 



through spars, drilling holes for trolley hangers or engineering 
points, cutting trolley cross-overs, etc. 

The work of the hammer drill in contracting replaces " mud 
capping " and includes block holing, " pop " shooting, drilling 
anchor bolt holes, breaking up old 
concrete or masonry foundations, 
piers, walls, etc., dislodging the sub- 
structure of old cable or conduit rail- 
ways, and removing rock in sewer, 
gas, water main or conduit trenches, 
cellars, shafts, wells, etc. 

A feature which cannot be too 
strongly insisted upon is the question 
of proper bits for the hammer drill. 
Neglect of this point alone often 
determines the whole difference be- 
tween success and failure. The 
hammer drill depends upon a large 
number of relatively light blows. A 
clumsy tool or improperly dressed 
bit may put a hole down by main 
strength and brute force with a pis- 
ton drill. But with a hammer drill 
striking up to 100,000 blows an 
hour, or 1,000,000 per day, a very 
slight difference in the quality of the 
steel, the exact angle of the cutting 
edges, the proper clearance and hard- 
ening, the number of cutting edges, 
whether one or eight, all are points 
which may make all the difference in 
the world. Disappointment or en- 
thusiasm rests largely on these very 
points, and they should be deter- 
mined exactly by intelligent experiment for every kind of 
rock. The conditions thus discovered should then be posi- 
tively maintained. 



Butterfly Valve" Telescope 
Feed Hammer or Stoping 
Drill. 



278 SUBWAYS AND TUNNELS OF NEW YORK 

The Ingersoll Drill and the Cameron Pump. It was in a 

little shop on the corner of Second Avenue and Twenty-second 
Street, New York, that both the Ingersoll drill and the Cameron 
pump originated, and the manufacture of both began under 
the same roof. The late Henry C. Sergeant, who is admitted 
to have done more in the invention and development of the rock 
drill than any other person, designed the first really successful 
Ingersoll drill, getting his fundamental ideas of the valve motion 
from Mr. A. S. Cameron. This was at a time when a reciprocat- 
ing engine, like a pump or a rock drill, with no crank shaft to 
carry it over the center, was practically unknown. The first 
machines of this class were built on steam engine lines, the 
valve itself being mechanically connected with or operated by 
the piston. In the first Ingersoll drill, as in the first direct- 
acting pumps, when the piston reached the end of the stroke 
it reversed the valve by direct mechanical contact with knuckle 
joints, rods or other devices, which intervened between the 
piston and the valve. 

Here is where great credit is due Mr. A. S. Cameron. He 
was seeking to perfect a pump which could be used in rough 
places where exposed parts were liable to wear or injury. He 
also wanted to design a valve which would open a large port 
at the end of the stroke the instant that the piston reached a 
certain point. This was hardly possible with a mechanically 
moved valve without excessive shock and wear. Cameron's 
invention, therefore, was to place a small tappet or knuckle 
in each cylinder head of the pump, which should serve as a 
trigger to trip and open, through contact with the piston, a small 
port connecting with one end or the other of the valve 
chamber. The valve itself was submerged in live steam pres- 
sure, equal on both ends, and hence when this tripping action 
took place it reduced the pressure on one end so that then 
the full pressure on the other end caused it to reverse. In 
order to do this with the minimum shock on the tappet, and also 
taking into consideration the importance of having a small port 
controlled by such action, Mr. Cameron used a plunger piston 
which in turn overlapped the valve itself, this plunger piston 



APPENDIX I 279 

having an area on each end which might be more or less accord- 
ing to the resistance of the valve to the action of sliding on its 
seat. The valve itself was, and still is, a slide valve, which, 
as everybody knows, rests tightly upon its ports and does not 
leak through wear. 

Sergeant had a problem more difficult than Cameron, because, 
in the first place, the piston speed of a pump is only about ioo 
feet per minute, while that of a rock drill is four times as great. 
This high speed made it difficult to use any kind of a tappet 
trigger, and, in order to get the quickest action of the valve, 
Sergeant sought to avoid the use of the slide valve and to use 
the plunger or valve-moving device of Cameron as the valve 
itself. In doing this he ran against another difficulty: the 
valve, in order to be tight on its seat, would press so hard that 
the speed of the drill became sluggish, and to remedy this he 
ran a bolt through the center of the valve, which relieved it 
of a certain portion of this pressure. 

Instead of the tappet trigger, Sergeant moved his valve 
by causing the piston of the drill to uncover passages leading 
alternately to each valve end. Here we have the identical 
principle, so far as valve movement is concerned, which is 
embodied in the Cameron pump — namely, an equal pressure 
on both ends of the valve, and the valve moving in consequence 
of reduction of that pressure on one end and the other alternately, 
the action itself being determined by the strokes of the piston. 
No better evidence is needed of the success of this valve action 
than the fact that the Ingersoll " Eclipse " drill and the Cameron 
pump are at work to-day with valves of this type. 

The community of interests between Cameron and Ingersoll 
has extended from this inception to the present day. The 
castings for the first air compressors of the Ingersoll make 
were made in the Cameron foundry on East Twenty-second 
Street. For many years, and until the Ingersoll works were 
moved to Easton, Pa., castings were made by Cameron. 

Adam Scott Cameron was the youngest of four brothers, 
all of whom took up mechanical pursuits. While a youth 
serving his apprenticeship, he was a student at Cooper Institute, 



280 SUBWAYS AND TUNNELS OF NEW YORK 

giving his nights and spare time to study and research. He 
graduated with honors, and at once applied himself to mechan- 
ical matters. He was early engaged in building the Sewall 
and Cameron crank-and-fly-wheel pump, which during the 
Civil War was in demand by the United States Navy and the 
merchant marine. At the close of the war the call for these 
pumps fell off, so that Mr. Cameron turned his attention to the 
design of a pump of greater adaptability and more general 
application. The standard Cameron pump was the result, 
its acorn-shaped air chamber being his trademark and con- 
tinuing up to the present time. He died at an early age, but 
before death he stamped his ability and force of character upon 
the mechanical engineering of his age. 



APPENDIX J 

TUNNEL CARRIAGE FOR DRILLING; ELECTRIC-AIR DRILL 

The illustrations herewith show two types of tunnel carriage 
recently brought out by the Ingersoll-Rand Company. The 
object of this device is to save time in setting up the drills in 
the heading, in removing them for blasting, and in starting 




Fig. 1 



drilling again after the blast, without serious interference with 
the mucking operations. The illustrations are almost self- 
explanatory. 

It will be noted that there is a truck with flanged wheels 
running on the ordinary tunnel track for muck cars. Upon this 
truck and arranged to swing in a vertical plane, is a long arm 
of structural steel shapes with an upright screw rod at the 
rear which is run out to roof and floor of the tunnel, fixing 
the arm rigidly in position. Upon this arm is a carriage 

281 



282 



SUBWAYS AND TUNNELS OF NEW YORK 



moved forward or back by a chain and crank; and this 
carriage supports a heavy drill bar swiveling in a horizontal 
plane. This bar carries the drills and has jack screws at 
its ends which are run out against the walls of the heading. 
A drop support beneath the long arm gives fruther rigidity to 
the mounting. 

Fig. i shows the tunnel carriage ready to be run into the 
heading, with the drills swung sidewise, the drill bar turned 
parallel with the arm, and the whole drawn back over the 
truck. All supports are free. Fig. 2 shows the tunnel car- 




Fig. 2 



riage in position for operation, with supports set. It will be 
noted that there is ample room beneath the arms and in front 
of the truck to permit mucking to proceed while drilling is 
going on. Standard drills are used, held in saddles on the drill 
bar. 

It will be readily seen that this type is susceptible of adap- 
tation to various conditions. Fig. 3, for instance, shows a 
modification in which the long swinging arm is dispensed with 
and the vertical adjustment of the drill bar is secured by means 
of a large central screw. The drills can be swung on the bar 
to drill holes in any position — up, horizontal, down, or side 
holes. While the illustrations show a 4-drill bar, it is evident 



APPENDIX J 



283 



that a longer bar for more drills could readily be used on this 
carriage. 

The Electric-Air Drill. By W. L. Saunders. Many members 
of the A.I.M.E., who participated in the visit made, during 
the Bethlehem meeting of February, 1906, to the shops of the 
Ingersoll-Rand Company, at Phillipsburg, N. J., inspected 
with interest the new Electric-Air drill, which the company 
had set up for the purpose of showing it in actual operation to 




Fig. 3 



American mining engineers. At the request of the Secretary 
of the Institute, I promised at that time to prepare a paper for 
our Transactions, describing the construction and advantages 
of the machine. But such a paper would then necessarily have 
contained much that was only expected or claimed by the 
designers and manufacturers of the drill, and not yet incon- 
trovertibly proved by varied and \ long-continued practice. 
However moderate such statements might have been, they 
would have given inevitably to the paper, to some extent at 



284 SUBWAYS AND TUNNELS OF NEW YORK 

least, the air of a prospectus, rather than of a technical contribu- 
tion. I therefore decided, with the secretary's approval, to 
postpone the writing of the promised paper until it could set 
forth the results of adequate actual practice, as well as the latest 
details of construction, etc., based upon practical experience. 
That period has now arrived. The Electric-Air drill has been 
exhaustively tested in the field, under varied and arduous 
conditions, and upon the hardest rocks. It is now fairly in the 
field; its merits and performances are matters of unimpeachable 
record, and its place among established competitors can be 
definitely determined. 

As a representative of the Ingersoll-Rand Company, as well 
as a member of the Institute, I may be permitted to add that 
my company, being largely interested in the manufacture of 
air compressors and machinery driven by compressed air, has 
no desire to injure its own business by claiming for this new 
machine that it should immediately supersede all existing 
applications of pneumatic transmission of power for drilling. 
On the other hand, if we had not satisfied ourselves that it has 
proved itself the best for given conditions, the company would 
not have risked its reputation by introducing it, and I, as a 
member of the Institute, would not have written this paper. 

In former contributions I have discussed the use of com- 
pressed air, and opposed, to some extent, the claims of the 
advocates of electrical power transmission in mining. I need 
not now retract any opinion thus declared. Many features 
of electrical transmission are undoubtedly convenient and eco- 
nomical; but the direct application of the electric current in 
rock drilling has long been a baffling problem; of which, in my 
judgment, the machine here described has furnished the first, 
and thus far the only, satisfactory solution, by combining the 
acknowledged advantages of air-driven percussion with the 
acknowledged advantages of electric power transmission, while 
avoiding the acknowledged disadvantages of both systems. 

The Electric- Air drill is correctly designated; it is not an 
electric drill, but an air drill, more completely an air drill than 
any other in existence, because it can be driven by air only, 



APPENDIX J 



285 



and not, like other air drills, by steam also. Yet, while it is 
thus distinctly air operated, the power of transmission is electric, 
and the sole connection of the drill with the power house is 
made by means of the electric wire, air compressors and pipe 
lines being entirely dispensed with. 

The illustration gives a general idea of the apparatus. It 
shows a rock drill which at first glance looks quite like the 
familiar air or steam-driven drill, mounted in the usual way and 
doing the same kind of work. Very near the drill, and con- 




Section of "Electric-Air" Drill and Pulsator. 



nected to it by two short lengths of hose, is a small air compres- 
sor, or, more properly, a pulsator, mounted upon a little truck. 
This constitutes the entire apparatus of a single drill. Each 
drill is accompanied by its individual pulsator in the same way, 
and each pulsator is connected to the line of wire from the 
power house. 

The usual drill shell is employed, and this may be mounted 
upon tripod, bar or column, according to the work. The drill 
cylinder fitted to slide in the shell is moved forward or backward 
by the feed screw. The cylinder is as simple as can be imagined: 
a straight bore with, at each end, a large opening and a boss to 



286 SUBWAYS AND TUNNELS OF NEW YORK 

which to attach the hose. The piston also is plain, much short- 
ened in the body, with a large piston rod which has a long 
bearing in a sleeve elongation of the cylinder. 

Upon the truck is mounted an electric motor, geared to a 
horizontal shaft with 180-degree cranks, which drive two single- 
acting trunk pistons, making alternate strokes in vertical air 
cylinders. One of these air cylinders is connected by the hose 
to one end of the drill cylinder, and the other end of the cyl- 
inder is connected by the other hose to the other air cylinder. 
The air, therefore, in either air cylinder, in its hose and in the 
end of the drill cylinder to which it is connected, remains there 
constantly, playing back and forth through the hose according 
to the movements of the parts, being never discharged and only 
replenished from time to time to make up for leakage. The 
propriety of calling the apparatus a pulsator instead of a com- 
pressor is evident. 

The essential details of the cycle of operation will be easily 
understood. We may assume, to begin with, that the entire 
system is filled with air at a pressure of 30 or 35 pounds. 
This pressure, being alike upon both sides of the drill piston, 
there will be no tendency for it to move in either direction. 
If now, the motor, instead of being at rest, is assumed to be 
in motion, one pulsator piston will be rising in its cylinder 
and the other piston will be descending in its cylinder; and, as 
a consqeuence, the pressure upon one side of the drill piston will 
be increased and the pressure upon the other side will be propor- 
tionately reduced, this difference of pressure causing the drill 
piston to move and make its stroke. Just before the drill piston 
reaches the end of its stroke, the movement of the pulsator 
pistons is reversed, preponderance of pressure is transferred to 
the other side of the piston, causing a stroke in the other direc- 
tion, and so on continuously. The drill thus makes its double 
stroke, or at least receives its double impulse, for each revolu- 
tion of the pulsator crank shaft. 

This is a sketch of the general principle of operation; we may 
now consider some of the details. The drill cylinder, while 
generally similar to that of the air or steam operated drill, is 



APPENDIX J 287 

in many respects quite different, and especially is it remarkable 
for its simplicity. The usual operating valve chest, the valve 
and the complicated means for operating it, the main air ports 
and the intricate little passages in and connected with the 
chest are all conspicuous by their absence, and nothing takes 
their place. The cylinder heads are both solid and both fastened 
securely in place. The split front head, the yielding fastenings 
for both heads, the buffers, the springs, the side rods, etc., 
of other drills are all banished. The cylinder is absolutely 
plain, with the boss at each end to which the hose is attached 
and the direct openings into the interior. 

The piston also has been simplified. The rotation device 
is necessarily retained, but the enlargement at the end of the 
piston rod, which constituted the chuck and necessitated the 
split front head, is not. The piston rod throughout is much 
enlarged, and a simple but effective self-tightening chuck is 
slipped on the end of it. 

The compressor or pulsator cylinders are as simple as the 
rest. There are no valves, either inlet or discharge, and there 
is no water jacketing nor the slightest need of any. The heat- 
ing of the air upon the compression stroke is compensated for 
by the fall of temperature accompanying its re-expansion, so 
that the air does not get hot and does not heat any of the parts 
with which it comes in contact. 

While this apparatus as a whole may appear complicated 
at first glance, it really is a great simplification, and the parts 
got rid of are those which have always been most troublesome 
and have entailed the most care and expense to maintain. 
The drill and the compressor or pulsator are each the simplest 
ever built. 

There are some minor details of this apparatus with which 
it is not necessary to burden this paper, and which would involve 
tedious explanation that all would not follow. In our descrip- 
tion of the principle of operation of the drill we assumed a 
mean air pressure of about 30 pounds in the apparatus, and 
it may be asked how this pressure is secured and maintained. 
When the pulsator is in operation the air pressure in the cylin- 



288 SUBWAYS AND TUNNELS OF NEW YORK 

ders both rises above and falls considerably below the mean. 
If at a certain point it is below that of the atmosphere, then 
a little valve provided will admit more or less air, this proc- 
ess continuing until sufficient air is supplied. In the begin- 
ning of operations the influx of air is rapid, so that no time is 
lost in getting sufficient pressure to begin with. The admis- 
sion and also the apportioning of the relative volumes of air 
to the two ends of the drill cylinder are easily adjusted by the 
operator. 

With the Electric-Air drill there is no freezing up or choking 
of the exhaust; the air also does not accumulate moisture and 
the temperature does not fall to the freezing point. The air 
does become and remains a constant vehicle for the conveyance 
and distribution of the lubricant, and with a certain amount 
of oil contributed to the system at regular intervals the problem 
would be how to prevent its reaching every working part rather 
than the reverse. 

The length of hose employed seems to be limited to about 
8 feet for each, and these may be attached to either side of the 
drill, but each always to its own end of the cylinder. This 
length of hose gives all necessary liberty for the location of 
the pulsator truck near the drill. The truck is of steel, with 
wheels usually made for the standard 1 8-inch mine track, but 
may be made for any other gage. When in use there is no 
necessity for any care in leveling the truck, as the pulsator will 
work at any angle at which the truck can stand. 

The motor may be either direct or alternating current, the 
latter being preferred because of the simple mechanical features. 
It is also smaller and lighter, a simpler and hardier machine 
and more nearly fool-proof. Several different speeds may be 
obtained with the direct and alternating current motor, full 
speed for steady running and considerably lower speeds for 
starting a hole or working through bad ground, with imme- 
diate transition from the one speed to another as required. 
The controller is on the top of the motor, and the operator 
at the drill can start, speed or stop the motor by simply pull- 
ing a cord, this being the only connection. The electrical con- 



APPENDIX J 289 

nection ends at the motor; both the hose and the cord insulate 
the drill and the operator is never exposed to the current. 

The Electric-Air drill strikes a blow normally so much harder 
than that of the air drill of the same capacity, that in many 
cases it is found advisable to dress the steels blunter or thicker 
to avoid breakage. The practical force of the drill was not 
first worked out in computation, but has been demonstrated in 
extensive practice and protracted experiment. The explana- 
tion has come later, but is clear and sufficient. 

The drill piston when running at full speed, making a stroke 
for each rotation of the pulsator crank shaft, will not strike 
either head. The hole by which the air enters the cylinder 
from the hose is not located at the extreme end of the cylinder 
or close to the head, but a certain distance away from it, so that 
when the piston approaches the head a certain portion of air 
is enclosed and acts as a cushion which first checks the advance 
of the piston and then shoots it back. The piston thus starts 
upon its working stroke impelled by a certain amount of force 
which, we may say, has been saved over from the preceding 
stroke to be utilized for this. The piston after being thus 
started is driven forward by an air pressure which increases as 
it advances, the pulsator piston being in the attitude of chasing 
and gaining upon the drill piston for a considerable portion 
of the stroke, while in the case of the ordinary drill piston, 
driven by a constant flow of air which it runs away from, the 
pressure must constantly diminish as the piston speed is accel- 
erated. In the same way by the action of the other pulsator 
piston the opposing pressure upon the advancing side of the 
drill piston is a diminishing pressure instead of the constant 
atmospheric resistance, and these combined cause a greater 
unbalanced difference of pressures upon the opposite sides 
of the drill, a more rapid acceleration of the piston movement, 
and a consequent higher velocity and force at the moment of 
impact of the steel upon the rock. 

Perhaps the most gratifying, and also surprising, revela- 
tion of all in connection with the Electric-Air drill is the now 
indisputable fact that it takes only one-third to one-fourth 



290 



SUBWAYS AND TUNNELS OF NEW YORK 



of the power, at the power-house, to drive it and do the same 
work as a rock drill of equivalent capacity. This is accounted 
for by the fact that the same air is used over and over and 
that all of its elastic force is availed of in both directions, 
instead of exhausting the charge for each stroke at full pres- 
sure. There are also no large clearance spaces to fill anew at 
each stroke, as these spaces are never emptied. 

A curious result of the mode of driving the piston of the 




" Electric- Air " Rock Drill on Quarry Bar Mounting. 

Electric-Air drill, and another valuable feature of it when in 
operation, is found in the trick the drill has of " yanking ' ; 
itself free when the bit sticks in the hole and of going on with 
its work again. When the bit of the ordinary air or steam 
driven drill sticks in the hole, that is the end of it as far as the 
drill is concerned, and it is for the drill runner to free it as best 
he may. He runs the feed up and down, hammers the steel, 
and coaxes things in various ways until the drill gets steadily 
running again. With the Electric-Air drill when the bit sticks 
the motor and the pulsator pistons do not stop, but keep running 



APPENDIX J 291 

the same as before. This means that if the drill piston is mak- 
ing, say, 400 strokes a minute it will, when it sticks, receive 
per minute 400 alternate thrusts and pulls with full force. Noth- 
ing could well be imagined more effective for freeing the bit, 
and often when it sticks, and before the runner can get ready 
to do anything about it, the drill is running right along again 
as if nothing had happened. 

The coming of the Electric-Air drill suggests many pos- 
sibilities, and ominously means much to the established interest. 
It necessarily suggests a revolution in methods and sometimes 
perhaps a superseding of the old plants throughout. In the 
working of the new drill the old central air compressor plants 
are absolutely worthless, but it is not easy to imagine any gen- 
eral abandonment of them. After all, the result may probably 
be that the new drill will not, to any great extent, drive out 
the old, but will make a new field of employment for itself, and 
in that way lead, as usual, to a considerable enlargement of 
the already extensive business which is behind it. 

As has been shown, the Electric-Air drill is as far as can 
be from being an electric drill, but it makes the ordinary 
electric current nearly everywhere obtainable immediately 
available for driving it. 

In the planning of installations which are new throughout, 
the Electric-Air drill is to be most seriously considered. The 
question of the relative final cost of operating this drill, or any 
other, is, after all, the decisive one, due recognition being given 
to the peculiarities of each, favorable or otherwise, which are 
not computable, but which still have their weight in determining 
our selections, " other things being equal." 

When the Electric-Air drill is operated without its own 
generating plant, the current being taken from a large power 
company, some very low figures are already on record. At 
Idaho Springs, Colo., a mine shaft was put down 67 feet in 24 
shifts and the total power cost was $24.00 for the entire work. 

In making rock excavations for building purposes in New 
York City and elsewhere, steam drills, having a temporary 
boiler installation, are frequently used. The Electric-Air drill 



292 SUBWAYS AND TUNNELS OF NEW YORK 

not only avoids the expense of the boiler equipment, but will do 
the work at a much lower cost, the current being supplied by 
one of the big electric power companies. Proceedings of Am. 
Inst, of Mining Engrs. 

Two Electric- Air Drill Records, with Costs. The Brier Hill 
Collieries of Crawford, Tenn., have been using one of these 
drills, a " 5-D," in their mines for about eighteen months for 
drilling holes in the roofs of several entries. The rock varies 
from slate to sandstone and conglomerate rock; and Mr. E. 
B. Taylor, general manager of the mines, who has kindly fur- 
nished us with the information regarding this drill, states that 
the drilling was done through the hardest roof he had ever 
encountered in thirty years' mining experience. 

A " 5-D " drill is equivalent to an Inger soil-Rand 3 J -inch 
air drill, and has a stroke of a little more than 8 inches. It 
will drill a 16-foot vertical hole from if to 2| inch in diameter. 
It has a 5! h.p. motor. Such a drill is intended for the heaviest 
work in large tunnel headings, open cut work in quarries or 
railroad gradings, in shaft sinking, or in mining. 

During sixteen months' work with this drill, holes were 
drilled in the roof of the main entry of one mine, a distance of 
600 lineal feet; in driving three entries of another mine, a dis- 
tance of 250 feet in a new haulway, 200 feet in the second left 
entry, and 275 feet in the third left entry. 

These three entries were driven simultaneously, the drill 
being moved from one entry to another as it was needed. One 
hole was drilled in the roof of each of these entries each day, 
the average depth of a hole being 7 feet. It took the drill run- 
ner and a helper from twenty to thirty minutes to unload the 
drill from a car and set it up, while the hole was drilled in about 
twenty minutes. About a half day was consumed in drilling 
the three holes and making the necessary moves, more than 
three-quarters of the time being taken up in moving and setting 
up the drill. 

With wages for the drill runner at $3.50 for a nine-hour 
day and $2.00 for the helper, this gives a labor cost of 13 
cents per lineal foot of drilling. Upon one occasion the crew 



APPENDIX J 293 

drilled seven holes in a nine-hour shift, aggregating 42 feet 
6 inches, which substantiates the cost of 13 cents per lineal 
foot. Mr. Taylor states that during the 16 months this 
work was going on, outside of sharpening the steel bits, not 
one cent was spent in repairs or for maintaining the drill — a 
rather unusual record for any drill. 

The Superior Portland Cement Company of Superior, Ohio, 
have three " 5-C " drills at work in their limestone quarries. 
We are indebted to Mr. J. B. John, manager of the company, 
for the following account of work done by these drills. 

The vein of limestone averages about 8 feet in thickness. 
To blast out this limestone, holes 6 feet deep and 2? inches in 
diameter are drilled. Each drill puts down, on an average, 
17 of these holes per day. Thus three drills do 306 lineal feet 
of drilling per day. There is blasted out an average of 500 
tons of limestone per day, equivalent to 1 .4 lineal feet of drilling 
per cubic yard of rock blasted, place measurement. 

With wages for the drill runner at $3.50 per day, and helper 
at $2.00 per day, this gives a cost for labor for drilling of 5.4 
cents per lineal foot, and 7.5 cents per cubic yard of rock blasted, 
which is a very low cost, accounted for, however, by the rapid 
drilling done by this machine. 

Another factor that enters into the rapid work done by one 
of these drills is its tremendous back-pull or stroke, making the 
drill work itself loose in a bad hole and preventing it becoming 
" stuck." Even when the steel binds, there is a pull and 
push on the piston, at full power, for every revolution of the 
pulsator; and this works it loose almost instantly. Mr. John 
states that the wear and tear on these drills has been very 
light. 

The method of moving the pulsator and motor in the quarry 
was very simple. These two are mounted on a common bed, 
which has two sets of wheels under it. A cheap wooden frame 
for a track was made in sections, for the truck to run on. Only 
a few of these sections were needed, and they were light, inex- 
pensive and easily handled. Small steel rails can also be made 
up in sections and used in the same manner, and naturally they 



294 SUBWAYS AND TUNNELS OF NEW YOKK 

will give better service, as well as allow of a better joint being 
made between the sections. When a good hard bottom occurs 
in the mine or quarry, the pulsator and motor can be moved 
from place to place without any track, the wheels running 
directly on the rock. On tracks it can be carried over rough 
ground or muck piles with the aid of blocks and tackle. — Engi- 
neering and Contracting. 



APPENDIX K 



ROCK DRILL BITS 



The success of almost every drilling operation depends 
on the selection and treatment of the bits. Too much attention 
cannot be given this important part of the work. If the bits 
have been properly formed, sharpened, and tempered for the 
work, and if they are changed just as soon as their edges and 
gages are worn, the result will be found to be most economical. 
The power drill sharpener has removed many of the short- 
comings attendant upon the hand-sharpening process, with 
the result that where these machines are used it is possible to 
accomplish from 25 to 100 per cent more drilling than under 
the old methods. The reasons for this are that the power 
sharpener turns out a much better bit. The saving in the 
blacksmith's wages should be a secondary consideration. The 
superior quality of the bits made in a machine will increase the 
capacity of the drilling machines sufficiently to pay handsome 
dividends on the cost of the power sharpener. 

For the guidance of those unfamiliar with the forms of 
drill-bits used in the different sections, I have prepared a few 
drawings of those in use. Fig. 1 represents the square cross- 
bit adopted as the standard for American mining practice. 
It is made from either round, octagon, or cruciform steel. In 
the copper mines of Michigan it is usually made of a round 
steel. In the iron mines of Michigan and Minnesota and 
wherever this form of bit is used east of the Rocky Mountains, 
octagon steel is preferred; but in the Rocky Mountain and Pacific 
States cruciform steel is used. The reason for the adoption 
of this form of bit as a standard will be appreciated when the 

295 



296 



SUBWAYS AND TUNNELS OF NEW YORK 



three requirements of a rock-drill bit are recalled. These are 
" to chisel out a hole in the rock," " to keep this hole round and 
free from rifles," and " to mud freely." There is really a 
fourth requirement, which is " to do as much drilling as pos- 
sible before being re-sharpened." 

The different kinds of rock to be drilled affect the wear of 
the bit. Very hard rock will blunt the chisel and reaming 
edges. The softer rocks do not blunt these edges, but wear the 
outer sides so that it loses its gage and size, still appearing 
to be quite sharp. For this reason a bit that is made with a 




Fig. 1 



Fig. 2 



Fig. 3 



Fig. 4 



Fig. 5 



square edge and a clearance angle of 8 degrees will drill about 
four times as long in soft rock as a bit with round edges and a 
clearance angle of 16 degrees, before being reduced to the size 
of the next bit that is to follow. Referring to Fig. i and Fig. 2, 
the latter being a round- edge bit with a clearance angle of 
16 degrees, it will be seen that in Fig. 1, the corners of the bit 
at the base of the bevel describe a circle that is equal to the 
circle that the chisel edges describe. This is as it should be, 
as it is impossible for the chisel edge to cut out all of the rock. 
The reaming edge, which is that part of the bit extending from 
the chisel edge to the base of the bevel, marked " A " in both 
Fig. 1 and Fig. 2, must ream the outer edge of the hole and keep 



APPENDIX K 297 

it round and free from rifles. In Fig. 2 it will be noted that the 
circle described by the corners of the bit at the base of the bevel 
is much smaller than the circle described by the chisel edges. 
This causes an excess of wear on the corners of the chisel edges, 
the bit rapidly loses its gage, as well as its efficiency, and it 
is almost impossible to keep the hole round. Rifles form and 
these cause the rotation parts of the drilling machine to break, 
often resulting in the loss of the hole. 

The angle of the bevel of the face of the bit has to do with 
its life, as well as with the property of " mudding " freely. 
It is generally accepted that if this angle be 90 degrees it gives 
strength and permits the bit to " mud " or throw back the 
cuttings from the face of the bit when the drill is pointed down- 
ward. Bits made like Fig. 19 and Fig. 20 will not " mud " 
freely. Another reason why bits such as shown in Fig. 1 
are preferable to those illustrated by Fig. 2, is that having a 
long wing they are stronger and will not break so readily as 
does a short bit. 

The^Simmons bit, used at the Champion mine at Beacon, 
Mich., is shown in Fig. 3. In it two of the wings are devoted 
entirely to reaming and keeping the hole round and free from 
rifles. Some tests made several years ago in jasper, the hardest 
rock found in the Champion mine, using a 2|-inch Rand drill 
with 60-pound air pressure at the compressor, showed an average 
speed per minute of 0.28 inches for the ordinary cross-bit, and 
0.659 inches for the Simmons bit. Both forms were hand- 
sharpened. 

The B run ton bit, the invention of the well-known mining 
engineer, D. W. Brunton, is extensively used in Idaho and 
Montana. It is shown in Fig. 4. The object of this bit is to 
obtain the advantages of the X-bit without the attendant dif- 
ficulties of resharpening. With this bit, as in the case of the 
X-bit, the piston must revolve a half turn before the cutting 
edges will strike in the same place a second time. It is as easily 
resharpened as the regular square cross-bit. The X-bit itself 
is shown in Fig. 5. Since the invention of power-drill sharpen- 
ing machines, this bit is fast disappearing. The reason will be 



298 



SUBWAYS AND TUNNELS OF NEW YORK 



understood when a comparison is made with the regular square 
cross-bit as made with the power-sharpener, and the cross- 
bits as they are resharpened by hand, shown in Fig. 18, Fig. 19 
and Fig. 20. The X-bit is designed to prevent rifles. This 
the hand-sharpened cross-bit would not do, but the machine- 
sharpened cross-bit effectually accomplishes. Fig. 6 shows 
what is commonly termed the high-center bit. This was for 
many years accepted as the proper form. It is still used in the 
mines of Cornwall and where Cornish customs prevail. Since 
the introduction of hammer drills this bit is again finding favor. 



^ 

/ 




Vc- 



~>9 




Fig. 6 



Fig. 



Fig. 8 



Fig. 9 



Fig. 10 



It is of especial advantage in starting a hole, the high center 
immediately making an impression on the rock, whereas the 
square-faced bit requires a flat face for ready starting. For 
a starting bit in hammer machines it has no equal. Here, 
however, its advantages over the square bit end. Used as a 
bit to follow the starter, it is liable to follow slips and seams 
in the rock, causing crooked holes, which are sometimes lost 
before being finished. This the square bit will not do. Fig. 
7 shows a bit where the corners are in advance of the center. 
This is a fast cutting bit. The corners break up the rock in 
advance of the center, and leave little for the center to do; this 
causes the corners to wear fast, but still not to excess when it 



APPENDIX K 299 

is considered that they do most of the work. This drill will 
not follow slips and seams, will drill a round hole, and is easy 
on the drilling machine. The weak point of this form is that 
the leverage is so great on the corners that they are liable to 
break off if tempered too hard. Fig. 8 shows the round-edge 
bit, which is a favorite with some. In soft rock this is good, 
but in hard rock it permits rifles to form in the hole because 
there are no reaming edges. 

The Y-bit shown in Fig. 9 gives the advantage of plenty 
of room for the cuttings to escape. It is, however, quite diffi- 
cult to make and resharpen by hand. With the power-sharpener 
it can be made as easily as any other form. Fig. 10 shows the 
" bull " bit in use in the lead and zinc mines of the Joplin, 
Mo., district before the introduction of the power-sharpener. 
The extreme hardness of the limestone and flint in the sheet- 
ground of that district caused the ordinary cross-bit as made 
by hand to wear too fast. This dull bull-bit, therefore, had to be 
adoptetd. Drilling here was not a matter of cutting the rock, 
but of shattering it by impact. The power-sharpener has 
changed all this, and the American standard cross-bit as made 
in these machines is now used. As a result the capacity of the 
drills has been materially increased. In mines where hand- 
sharpening is still done the bull-bit is yet in use. Fig. 11 
shows the Z-bit used in hand-sharpening in the southeast Mis- 
souri lead district. This bit is also used quite extensively in 
Germany. In both places, however, the advantage of the 
standard square cross-bit as made with the power-sharpener 
is fast causing it to be displaced. Fig. 12 shows the " six- 
wing rosette " bit as made in the power-sharpener in use at the 
Penarroya mines of Spain. It is used in hammer drills only. 
Of all the rosette forms of bits, this has been found to be the 
most satisfactory. Fig. 13 shows the square cross-bits when 
made up for hammer drills where a hole for the introduction 
of air or water to remove the cuttings apexes at a point back 
from the bevel of the bit in one of the recesses between the 
wings. Fig. 14 shows the same form where the hole ends in 
the center of the cross of the cutting edges. This form of bit 



300 



SUBWAYS AND TUNNELS OF NEW YORK 



is extensively used. Its faults are that a core is formed by this 
hole; this core fills the hole, and causes a stoppage of air or 
water. These cores have been known to become as much as 
8 inches long, and are quite difficult to remove. To clear them 
away the core must be burned out by heating the steel the 







Fig-, n 



Fig. 12 



Fig. 13 



Fig. U 



Fig. 15 



full length of the core in a slow fire — a sometimes slow and tedious 
process. This difficulty is entirely overcome by the use of the 
bit shown in Fig. 13. The Z-bit, Fig. 15, is extensively used in 
Germany. In hammer drilling machines, the steel is formed 
in bars having a Z-shape. While I show this bar straight, 




Fig. 16 



Fig. 17 



Fig. 18 



Fig. 19 



Fig. 20 



it is usually twisted to form a spiral. It is an easy matter to 
form a Z-bit on the end of such a bar. The results obtained 
are excellent. Holes to a depth of 16 feet horizontal have been 
drilled with this form of steel. The spiral draws out the cuttings 
much the same as an auger. Fig. 16 to Fig. 20 are given to 



APPENDIX K 



301 



show the evolution of the cross-bit where hand-sharpening is 
employed. There are two systems of hand-sharpening. One 
is known as the set-hammer system. In it the steel is hammered 
by placing a set-hammer on the bevels and driving the steel 
back. The results of this method are illustrated in Fig. 16 to 
Fig. 19. Fig. 16 shows a bit made by cutting the bevels with a 
chisel, and is as it should be in form. Fig. 17 shows this bit 
after about the third sharpening. Fig. 18 is the same bit after 
about the sixth sharpening, and Fig. 19, is the same bit at 
about the time that the original cross that was formed on the 
bar of octagon steel has become exhausted. The other sys- 
tem of hand-sharpening is known as the fuller and dollie system. 
By this system the stock is first drawn sharp at the corners, as 




Fig. 21 



Fig-. 22 



Fig. 2'd 



Fig. 21 



Fig. 25 



shown in Fig. 20, with the fuller, after which it should be set 
back in the center with the dollie. Unfortunately the man 
swinging the sledge hammer gets tired before the bit is set back 
enough; the result is that the bit, partly finished, is left as 
shown in Fig. 20. It is because the power-sharpener has the 
staying power, and because it readily finishes a bit perfectly, 
that inferior bits like these are not to be found where machine 
sharpening is employed. 

After a bit has been forged, it should be properly tempered, 
as in Fig. 21. Fig. 22 shows the result of the common method 
of tempering. The center of the bit is soft, while the corners 
are hard. When the bit is immersed in the water about an inch 
the large mass of metal in the center cools more slowly than the 
corners, since the corners have three sides exposed to the water. 



302 



SUBWAYS AND TUNNELS OF NEW YORK 



Perhaps the center had not chilled at all when the bit is with- 
drawn for annealing, and the final result is a soft-center bit, 
which will flatten and retard the work of drilling. Fig. 23 
and Fig 24 show the result of trying to temper the bit with the 
forging heat, by plunging the whole bit into the water as soon as 
it is sharpened. The line of tension induced by cooling is indi- 
cated. At this place the drill will 'break. Fig. 25 shows the 
checking caused by first chilling the steel back of the bit and 
then plunging with the forging heat. 

For the purpose of tempering as shown in Fig. 21, a tank 
should be provided, such as is shown in section in Fig. 26. This 




Fig. 26. 



should be about 12 inches deep by 12 inches wide, and of suf- 
ficient length to accommodate whatever number of drills are to 
be sharpened in a day with the machine. The water inlet 
should be at the bottom, and the outlet should be placed about 
three-quarters of an inch above a grate, which itself should be 
about 8 inches above the bottom. This permits the bit to be 
immersed to a depth of about three-quarters of an inch. With 
a tempering tank of this construction the bit can be hardened 
to any desired degree. This depends on the temperature of 
the bit when placed on the grate. It is essential that the drill 
stand in a vertical position. To lean either way would cause 
it to harden to a greater depth on one side than on the other, 



APPENDIX K 



303 



r 





a 

.9* 



73 
a 



02 



t-i 

Q 







304 SUBWAYS AND TUNNELS OF NEW YORK 

causing a tension that might lead to breaking of the wings. It 
is best to provide a rail around the tank about the distance 
required to hold the shortest drill, and to drive pins about 
3 inches apart in this rail. By placing the drills between these 
pegs they can be kept in a vertical position. When using this 
tank a small flow sufficient to displace the water heated by the 
cooling of the bits should be turned on to keep the supply always 
cool. T. H. Proske, in Mining and Scientific Press. 

Cost of Sharpening by Hand at the Homestake Mine, as Made 
up in the Office of that Company. 

Blacksmiths. Helpers. 

Highland 2 $7 . 00 2 $6 . 00 

400 level 1 3-5° I 3 • °° 

600 level 4 14.00 4 12.00 

700 level 3 10.50 3 9.00 



$35.00 $30.00 $65.00 
120 drills to the man and helper. 
1,200 pounds of black coal 7 . 20 



$72.20 

Cost of Sharpening with Machine, at the Homestake Mine. 

$72.00 

1 machine, air to run same $2 . 00 

2 blacksmiths, $7.00; 2 helpers, $6.00 13. 00 

2 blacksmiths sharpening block hole steel 7 . 00 

2 extra tool packers 6 . 00 

720 pounds coke 4.75 

Fire brick to repair furnace 20 



$32.95 32.95 



Saving per day $39 . 25 

1,000 drills, 2 shifts, 10 hours each. 

Machine-sharpened drills last better than those sharpened 
by hand and do not break as many bits, so there is a saving of 
steel. 



APPENDIX K 305 

" One machine is sharpening steels for one hundred drills 
with less waste of steel and only about one-tenth the number of 
broken bits to trim that there were when hand-sharpening was 
employed." 

Rock Drill Sharpening Arrangements. Drill sharpening 
presents a department of mine costs to which no attention is 
given by stockholders, and only a moderate degree of attention 
by the mining companies. An important step was taken 
several years ago in reducing the cost in this department by 
the invention of the mechanical drill sharpeners, actuated by 
compressed air, which have now been introduced in the shops 
of nearly all the mining companies; but aside from this the com- 
panies themselves took no step to economize along this line 
except to introduce the machines and thus reduce the labor 
costs. 

A radical departure is now being introduced, however, at 
a number of mines that will bring about even a greater saving 
than was secured when mechanical drill sharpeners were intro- 
duced. This is to alter the system of handling the drills. To 
show the comparison of the new system with the old, the method 
formerly employed will first be enumerated. 

The drills are assembled underground by the drill boys, 
loaded on skips and hoisted to the surface. The ordinary rock 
skips are generally used for this purpose, and at times the long 
drills create a factor of danger, projecting above the skip bail 
and occasionally catching in the walls of the shaft. 

At the surface the drills are piled out upon the floor by 
the drill boys, generally in disorderly heap, which at times 
bends the steel so that it has to be heated and straightened, 
thus drawing its temper. Some of the companies have special 
skips, with compartments in which the steel is laid in an orderly 
manner, and thus the danger of catching and bending is removed. 

The drills are then loaded into wagons, in most cases, and 
hauled by teams to the drill shop, where from two to half a dozen 
drill sharpening machines are employed, depending on the size 
of the mine. Each team, driver and helper in this service costs 
about $5.50 per day. 



306 SUBWAYS AND TUNNELS OF NEW YORK 

After the drills are sharpened they are returned to the under- 
ground service by reversing the steps already described. This 
method requires that the drills be handled from six to ten times. 
Each drilling machine underground requires about 1500 pounds 
of drills every twenty-four hours, and the cost of sharpening 
will at times reach $7.50 per day to keep the drills of one machine 
sharpened. 

A complete change in this system is now being devised, 
to be introduced later. There is being installed in each shaft 
house a drill sharpening shop, consisting of a fireproof room, 
a forge and a drill sharpening machine, with the few other nec- 
essary tools. Two drill skips will be provided at each shaft, 
with compartments in which the drills will be kept assorted by 
lengths. When a skip load of drills comes to the surface it will 
be detached from the hoisting cable and shunted from the tracks 
of the skip way into the sharpening shop, which will be inside 
the shaft house structure and not 20 feet from the collar of the 
shaft. 

In the shop will be an empty drill skip; and as each drill 
is taken from the loaded skip and sharpened it will be placed in 
the empty, until the latter is full and ready to attach to the 
hoisting cable to be lowered into the mine, leaving the former 
loaded skip empty and ready for the next consignment. 

There will be only one to three hours' work at each shaft, 
according to the volume of rock, and the sharpeners and helpers 
will make their rounds from shaft to shaft handling the work. 
No one will be employed in the service except the drill boys 
necessary to make the underground distribution, and the neces- 
sary sharpeners and helpers on the surface. — Copper. 



\ 



APPENDIX L 

EXPLOSIVES; DAMPNESS AND DYNAMITE; BLASTING GELATIN; 
COST OF BLASTING IN OPEN CUTS 

Selection of Explosives for Tunnel Blasting. The selection 
of explosives for tunnel blasting probably requires a more care- 
ful study of conditions than for any other kind of excavating. 
Maximum speed in driving cannot be attained unless the explosive 
best adapted to the work is used. When starting a tunnel or 
drift, it is a good plan thoroughly to try out several explosives 
which are distinctly different in action before finally adopting 
any one of them. The results, however, from this preliminary 
trial will be of little or no value, unless all the explosives are 
used under exactly the same conditions. Care must be taken 
to see that no change occurs in the character of the rock, number 
and direction of the bore holes, strength of the detonator, kind 
and quantity of tamping, amount of water encountered, method 
of connecting up the bore holes for firing, and that the explosive 
is always thoroughly thawed. If a material change in any 
of these conditions occurs as the work progresses, further tests 
should be made to determine whether a quicker or slower, a 
stronger or weaker, explosive might not break the ground, or 
bottom the bore holes better, or make it possible to bring out 
the cut with fewer holes or deeper ones. The speed at which 
rock can be drilled does not indicate how it will break, and not 
infrequently that which can be easily drilled is very difficult 
to blast. 

High explosives suitable for tunnel blasting should not 
give off objectional fumes on detonation, and accordingly 
gelatin dynamite, blasting gelatin or ammonia dynamite should 
always be selected. Gelatin dynamite is made in various 
grades of strength, from 25 to 80 per cent inclusive. It is 

307 



308 SUBWAYS AND TUNNELS OF NEW YORK 

comparatively slow in action, the higher grades being little, 
if any, quicker than the lower ones. Blasting gelatin is manu- 
factured in only one strength, which for comparative purposes 
may be said to be ioo per cent. It is more powerful and quicker 
acting than any other blasting explosive. It should be used 
sparingly, therefore, until the maximum safe charge has been 
learned from experience. Good results will often be had in 
hard ground, if a few cartridges of blasting gelatin are used in 
the point of the bore hole, with gelatin dynamite on top. When 
this is done, it is best to put the detonator in one of the car- 
tridges of blasting gelatin. Ammonia dynamite is made from 
25 to 75 per cent strength. All grades are quicker than gelatin 
dynamites and, generally speaking, the quickness increases 
with the strength — that is, the stronger grades are quicker, 
and the lower grades of these three high explosives offer a wide 
range in strength and quickness to select from, and it is always 
possible, after a few trials, to find an explosive exactly suited 
to the conditions. 

Railroad tunnels, mine tunnels and drifts, highway tunnels, 
and irrigation tunnels, are being driven daily through various 
kinds of " ground." Often it is a matter of first importance to 
finish them quickly, and consequently details in regard to 
methods and equipment are matter of general interest. Within 
the past few months, a number of speed records in tunnels of 
different sizes have been made, and descriptions of them have 
appeared in various technical magazines. 

In Engineering-Contracting of Oct. 20, 1909, Mr. J. B. Lip- 
pincott, assistant chief engineer of the Los Angeles aqueduct, 
gave an interesting account of the driving of the Red Rock 
Tunnel of the Los Angeles aqueduct system. In August, 1909, 
this tunnel, which is 9 feet 10 inches by 10 feet 8^ inches in 
section, was advanced 1061.6 feet. Mr. Lippincott states that 
the explosives used were Du Pont 40 per cent ammonia dynamite 
and blasting powder. 

In the Engineering News of Nov. 18, 1910, the Red Rock 
Tunnel is again referred to, and details are also given by Mr. 
,C. H. Richards, division engineer, in regard to a tunnel on the 



APPENDIX L 309 

Little Lake Division of the Los Angeles aqueduct. The 
explosives used in this tunnel were Hercules 40 per cent and 60 
per cent gelatin dynamite, the average weight of explosives 
per cubic yard of rock, place measurement, having been only 
3.3 pounds, or about 35 pounds per lineal yard of tunnel, almost 
10 by 10 feet in section. 

A short time before, accounts were given in several mining 
magazines of a record driving speed made in the Roosevelt 
drainage tunnel at Cripple Creek, Colo. The explosives used in 
this tunnel were 40, 50 and 60 per cent Repauno gelatin dyna- 
mite and Du Pont blasting gelatin. 

A very interesting description of the Rondout pressure 
tunnel of the Catskill Aqueduct, written by Mr. John P. Hogan, 
assistant engineer of the New York City Board of Water Supply, 
was published in the Jan. 1, 1910, number of the Engineering 
Record. Very rapid progress was made in this tunnel, and also 
in the Moodna pressure tunnel of the same system, described 
in the Engineering Record of June 4, 19 10. The explosive 
which gave best results, and which was used exclusively in 
both of these tunnels, was 60 per cent forcite — a gelatin dyna- 
mite. 

Reference to a paper by B. H. M. Hewett and W. L. Brown, 
on the land sections of the Pennsylvania Railroad North River 
tunnels, published in Vol. XXXVI of the Proceedings of the 
American Society of Civil Engineers, and reprinted in part in 
Engineering-Contracting of May 11, 19 10, shows that 40 per 
cent forcite was used in blasting on the Manhattan section, 
and 60 per cent forcite on the Weehawken section. 

The records of many other tunnels recently constructed 
further illustrate how many kinds and strengths of explosives 
are used for blasting under the different conditions encoun- 
tered in one class of work. 

The specific cases referred to above were all connected 
with large and important contracts, where equipment and 
methods were of the best; and several of these tunnels were 
driven at record speed. The fact that so many different explo- 
sives were used in the seven tunnels goes to show that care was 



310 



SUBWAYS AND TUNNELS OF NEW YORK 



taken to use the explosive which was best adapted to the con- 
ditions; and it is not unlikely that the speed of driving these 
tunnels was largely due to the attention given to the selection 
of the explosives. 

This point is equally important when driving narrow tun- 
nels and drifts. After a study of the rock in a cross-cut 3 feet 
6 inches by 7 feet, in the Calie shaft at Cripple Creek, it was 
decided that best execution would be given by a 40 per cent 
gelatin dynamite. Repauno 40 per cent gelatin was accord- 
ingly adopted, and it was necessary to drill fourteen holes as 
shown in Fig. 1, from 3 feet 6 inches to 4 feet six inches deep 




SECTION E-F 



SECTION AB AND C-D 



Fig. 1. 



and blast them with about 35 pounds of 40 per cent gelatin 
dynamite, in order to advance the tunnel about 3 feet. In 
an attempt to increase the speed of driving, and to reduce the 
cost, the face was drilled with eleven holes, as shown in Fig. 
2, and these holes were loaded with Du Pont blasting gelatin 
in the points, and Repauno 40 per cent gelatin dynamite on 
top. In this method of loading about 7 pounds of the blasting 
gelatin and 1 7 pounds of the gelatin dynamite were used, making 
a reduction of about 15 per cent in the cost of explosives, and 
20 per cent in the amount of drilling, while the tunnel was still 
advanced fully 3 feet each shift. Here the adoption of a more 
suitable explosive for the work resulted in a great reduction 



APPENDIX L 



311 



in cost instead of increase in speed. Engineering and Contract- 
ing, July 27, 1910. 

Dampness and Dynamite. Dynamite should never be 
stored in tunnels nor in any place where dampness exists. 
Although a tunnel may seem dry, all rock-in-place contains 
from 3 to 8 per cent of moisture, which is continually being 
brought to the wall-surface in underground workings by cap- 
illarity where it is evaporated unless, for want of ventilation, 
the air is saturated. Thus the rock is continually contributing 
moisture, which is greedily absorbed by the sodium nitrate in 
the dynamite, that salt being highly hygroscopic. As soon as 




section e- F 



SECTION A-B AND C~D 



Fig. 2. 



the sodium nitrate has deliquesced — that is, melted from absorp- 
tion of moisture — the homogeneity of the dynamite becomes 
distributed, and the " dope " fails to retain the nitroglycerine, 
which then leaks out. The watery substance often seen on 
cartridge-paper, and the oily stain seen in dynamite boxes, is 
due to the leaking of the nitroglycerine. A cartridge in this 
condition is far more liable to accidental explosion than sound 
dynamite, and it is perilous and uneconomical in use. It will 
not develop the same energy as good dynamite; it is likely to 
burn and blow out instead of detonating properly; and it is a 
frequent cause of " misfires," and of the failure of a charge to 
explode to the bottom of a hole. Mining and Scientific Press. 



312 SUBWAYS AND TUNNELS OF NEW YORK 

Blasting Gelatin. Blasting gelatin consists of about 92 
per cent nitroglycerine and about 8 per cent gun cotton. It 
is the most powerful explosive manufactured, not excepting 
clear nitroglycerine. Because of its high detonating power 
it is erroneously supposed to be more dangerous to handle 
than ordinary grades of dynamite; but, owing to its gelatinous 
composition, it is no more sensitive than 40 per cent H. G. 
dynamite. In appearance it is somewhat similar to gelatin 
dynamite, although more elastic and gelatinous. It is rec- 
ommended for use when a much more powerful agent than the 
60 per cent dynamite is desirable. It gave exceptionally good 
results in a tunnel driven through hard granite where 60 per 
cent gelatin dynamite failed to break out ten-foot holes satis- 
factorily. 

The blasting gelatin in this work was used in the cut hole:; 
only, and then only made up about one-third of the charge, 
the remainder of the charge being of 60 per cent gelatin dynamite, 
which was loaded on top of the blasting gelatin. 

Cost of Blasting Rock in Open Cuts. In tunnel work more 
explosive must be used than in open cut, yet the amount may 
be estimated more closely as there are records available of the 
quantities used. The weight of explosive used in tunneling, per 
cubic yard, varies from 3 to 10 pounds, according to the char- 
acter of the rock, and the shape and size of the tunnel. In 
small mining tunnels, or adits, and in tunnels for sewers, the 
amount of explosive used will be much greater per cubic yard 
than in larger tunnels. 

Some wonderful results in tunnel driving have been accom- 
plished during the past decade by adopting definite methods 
of drilling, loading and firing holes. 

The following data of the cost of explosive in open cuts are 
from Daniel J. Hauer, in The Contractor. 

Example I. In mountainous sections of the country certain 
materials, such as indurated clay, cemented gravel and similar 
earths, frequently classed as hardpan, cannot be plowed and 
excavated with scrapers, owing to the steepness of the cuts 
and embankments. So the excavation is made with carts or 



APPENDIX L 313 

small cars in a manner similar to rock work. Such was the 
case in this example. The material was indurated clay, with a 
few sandstone boulders in it. As picking was very expensive, 
the cut was shot with black powder, and a small amount of 
40 per cent dynamite was used to spring the holes and break 
up some of the largest boulders. Under the specifications the 
material was classified as 24 per cent loose rock (there being 
no hardpan classification) and 76 per cent earth. 

The price paid for explosives was $1.20 per keg for black 
powder, FF and FFF grade being used; n| cents per pound 
for 40 per cent nitroglycerine dynamite; 42 cents per 100 feet 
for double tape fuse; 75 cents per hundred for caps; and from 
4 to 7 cents each for electrical exploders, according to their length. 

The cost per cubic yard for explosives for this piece of 
excavation was 2.5 cents, there being used .40 pound of black 
powder for each cubic yard of material excavated. The work 
was done in September and October, good weather prevailing. 

Example II. This was a large cut in cemented gravel, with 
only a few sandstone boulders in it. It was almost impossible 
to pick the material until it was shot. Much of the gravel ran 
in cobble sizes. The material was harder to excavate than in 
Example I. About two-thirds of the cut was gravel and boul- 
ders, the rest being earth. The work was done during the months 
of December, January and February, when the ground was 
frozen. 

The cut was excavated in a manner similar to the previous 
example, small cars being used instead of carts, and nitro- 
granular was used to shoot the material instead of black powder. 
Forty per cent strength of nitro powder was also used instead 
of dynamite for springing holes and breaking large boulders. 
The price paid for nitrogranular was nine cents per pound, 
and ten and one-half cents for nitro powder. The prices of 
other materials were the same as in the previous example. 

The cost of explosive per cubic yard for this work was 1.7 
cents, while .16 of a pound was used per unit. This is a low 
record. The costs given do not include any labor nor drilling, 
covering only the blasting materials. 



314 SUBWAYS AND TUNNELS OF NEW YORK 

Example III. In excavating earth with steam shovels, even 
where rock does not occur, it is well to do light blasting, espe- 
cially when the cutting is deep. Only enough explosive 
should be used to shake the ground and not throw it down. 
Then the shovel will work faster, since the material will run 
to it as it digs, and time will not be lost through caving of the 
high banks on the shovel. This last consideration is an import- 
ant one, as much time is lost by cave-ins, and in addition the 
shovel is frequently injured, and men are often crippled or killed. 

On one job six hundredths of a pound of black powder was 
used per cubic yard of material. The holes were drilled to grade 
and sprung with light charges of dynamite, the material to be 
excavated being " averaged earth." The price of black powder 
was $1.10 per keg. The cost per cubic yard for explosives was 
0.33 cents. It was found that this shooting was too light, as 
the material was not shaken up enough to prevent cave-ins, 
so on another job a new method was used. The holes, sunk 
with a well driller, were put from 3 to 5 feet below grade, and 
were not sprung. With these holes the charges were increased 
to two-tenths of a pound per cubic yard, making a cost of 0.9 
cents per cubic yard. The material was a little harder, but 
cave-ins no longer occurred. However, the cost was deemed 
excessive, since, with the drilling and labor of loading, it 
amounted to about 1.5 cents per cubic yard. 

Judson powder, or contractors' powder, was used in place 
of black powder, with the result that only six hundredths of a 
pound was needed, and the cost per cubic yard for explosives 
was 0.48 cents. Just as efficient work was done, thus proving 
that Judson was better adapted to this class of blasting. The 
Judson on this job cost seven cents per pound. 

Example IV. The material in this cut was. clay, shale, boul- 
ders and sandstone ledges, being classified as 35 per cent earth, 
35 per cent loose rock, and 30 per cent solid rock. Black 
powder at $1.20 per keg was used for blasting, and 40 per cent 
dynamite at nf cents per pound was used for springing and 
breaking up boulders; 0.46 pound of black powder was used 
for each cubic yard of material, and 0.12 pound of dynamite, 



APPENDIX L 315 

making a total of 0.58 pound and a cost of 4.3 cents per cubic 
yard. 

Example V. The material in this case was very similar to 
the above, there being a little less solid rock. Instead of black 
powder for the heavy blasting, Judson powder at 7} cents per 
pound was used. Each cubic yard took 0.26 pound of Judson, 
and only 0.04 pound of dynamite, a total of 0.30 pound, making 
a cost of 2.5 cents per cubic yard. These two examples make 
an interesting comparison, showing that the Judson gave more 
economical results, since the slight difference in the amount 
of solid rock would not account for the great variation in the 
amount of explosives used and in the cost. This statement 
is verified by the next record. 

Example VI. Here all the material was solid sandstone 
ledges, there being three times as much solid rock as in Example 
IV. As black powder was used on this work, an easy com- 
parison is made. In all 0.70 pound of explosives was used, 
0.47 pound being black powder and 0.23 pound dynamite. The 
cost was five cents per cubic yard. These examples show 
that the black powder loosens the material, but it is necessary 
to use a large amount of dynamite to break up the material so 
that it can be moved. It must be remembered that in all of the 
cases given here, except the steam shovel work, the material 
was moved by hand, either with dump carts or small cars. 

Example VII. This example and the following one are given 
to illustrate how expensive work can be made by the wrong 
method of blasting. As a rule, in excavating rock cuts, the 
cut is breasted, and then one or two holes are exploded, accord- 
ing to the material or the width of the cut. This method gives 
a free face for the explosives to work upon, thus obtaining from 
them their most effective power. 

In these two examples it was decided to drill holes along 
the center line of cuts that were to be 20 feet wide on the bottom 
and to explode them all at one time. The material was a solid 
sandstone, occurring in ledges, being classed entirely as solid 
rock. In order to charge the holes sufficiently, they had to be 
sprung excessively, which was expensive in the use of dynamite. 



316 SUBWAYS AND TUNNELS OF NEW YORK 

Judson was used to charge the holes, sunk about 2 feet below 
the grade of the cut. 

For this work 0.65 pound of Judson was used per cubic 
yard, and 0.60 pound of dynamite, making a total of 1.25 pounds, 
and a cost of 12.4 cents per cubic yard. 

Example VIII. This too was all solid sandstone, shot in 
the same manner as above. A total of 1.89 pounds of explosives 
was used, being 0.89 pound of Judson and one pound of dynamite. 
The cost per cubic yard was 23 cents. In Example VII. the 
depth of the cut was from 16 to 20 feet, while in this case 
the cut was more than 30 feet in depth. In the first case 
the depth was not too great to have worked with one lift, but 
the 30 feet was too deep for one lift, especially when the cut 
was not worked to a breast. The result of this method of 
blasting was not to throw down any material, even when the 
large blast was made, and the entire top of the cuts had to be 
quarried off with dynamite, since they were ruptured so that 
it was not possible to use either black powder or Judson to break 
it up. The bottom of the cuts, where the full force of the 
Judson was felt, was broken up too much, as much of the rock 
was pulverized. If these cuts had been worked to a breast, 
the results would, no doubt, have been as satisfactory as those 
of Example V, and in the following. 

Example IX. This was all sandstone, being classified as 
88 per cent solid rock and 12 per cent loose rock. The work was 
done in the winter time, during the months of January, February, 
March and early April, while the work in the other two cases 
was done during excellent autumn weather. The rock was well 
breasted before being shot, and was blasted so that little dyna- 
mite was needed to break up the boulders. In nearly every 
case it was not permissible to waste any of the rock, else the cuts 
could have been blasted more heavily, and there would have been 
less boulder breaking. 

Judson powder was used for the heavy blasting, taking 0.35 
pound per cubic yard and 0.17 pound of 40 per cent dynamite, 
a total of 0.52 pound, making a cost of five cents per cubic yard. 

Example X. A similar piece of sandstone excavation being 



APPENDIX L 317 

classed as 2 per cent earth, 15 per cent loose rock and 83 per 
cent solid rock was blasted with black powder, being first 
breasted. There was used 0.70 pound of black powder and 
0.50 pound of dynamite, a total of 1.20 pounds. The cost per 
cubic yard was twelve cents, the work being done in the middle 
of winter. 

Example XL This was another case of bad judgment shown 
in blasting. The cut was a side hill — one of solid sandstone — 
with the rock at an angle of about 45 degrees. The greatest 
depth of cut was not over 8 or 9 feet. After shooting off the 
toe of the rock, holes were drilled at the upper slope and sprung. 
It was then found that the rock was very hard, so that the holes 
did not chamber readily, and when the heavy charges for 
springing opened up seams and cracks, the rock settled back 
into its old position. A considerable amount of dynamite was 
wasted in springing. The foreman was directed to shoot the 
holes with straight dynamite after springing only twice, but 
he continued springing, and besides loaded the holes with black 
powder and dynamite. The black powder cost $1.35 per keg 
on this job, and the dynamite twelve cents per pound. When 
the blast was made, the dynamite did all the work that was done, 
and the powder was ignited by it, burning for over five minutes 
after the rock was thrown down. 

Two different explosives, as black powder and dynamite, 
should not be used in the same hole. Dynamite explodes by 
detonation and black powder by ignition, so the former will 
act a little quicker than the latter, always robbing it of its effect. 
This is what occurred in this case, and the black powder was a 
total loss. These holes should have been shot with dynamite 
alone. 

There was used 2.05 pounds of dynamite to each cubic yard, 
making a cost of 27 cents per cubic yard. In addition, 2 
pounds of black powder was used to each cubic yard at a cost 
of 10.8 cents, making a total of 4.05 pounds of explosives, and a 
total cost of 37.8 cents per cubic yard. To an experienced man 
these figures reveal incompetency. 

Example XII. This was solid sandstone, but instead of 



318 SUBWAYS AND TUNNELS OF NEW YORK 

using either black powder or Judson, nitrogranular was used 
for the blast and nitro powder for springing the holes and break- 
ing boulders. The granular cost 9 cents per pound and the 
nitro powder ioj cents. 

There was used 0.24 of a pound of nitrogranular per cubic 
yard and 0.17 of a pound of nitro powder, a total of 0.41 of a 
pound, at a cost of 3.5 cents per cubic yard. This, by com- 
parison with the other examples given, shows a low cost. 

Example XIII. This was a sandstone cliff that had to be 
thrown down a mountain side into a river. Nitrogranular 
was used, and a small amount of nitro powder to spring the holes. 
The blasts are successful, throwing all but a little of the mate- 
rial into the river, so that the labor of drilling and loading and 
the cost of explosives was almost the entire cost of excavation. 
More explosives were used in this case than in Example XII, 
since in that cut there was to be no waste, while in this case all 
the material was to be wasted. 

There was used 0.31 pound of nitrogranular and 0.02 pound 
of nitro powder, a total of 0.33 pound, at a cost of 3.7 cents 
per cubic yard. 

One lesson clearly indicated from these examples is that 
Judson powder and nitrogranular save money in blasting as 
compared with black powder. 

In some cases money is saved in the first blast, while much 
dynamite is also saved in breaking up boulders and in pop- 
holing the bottom of cuts. 

Another lesson is that rock cuts should always be breasted 
up before being shot, especially if the cuts are of considerable 
depth, otherwise much of the force of the explosive is lost. 



APPENDIX M 
PUMPS FOR SINKING AND TUNNELING; SINKING CAISSONS 

The first attempts at the construction of hydraulic machinery 
were made in the Greek school at Alexandria about 120 B.C., 
when the fountain of compression, the siphon and the forc- 
ing pump were invented by Ctesibius and Hero; and though 
these machines were operated by the pressure of the air, yet 
their inventors had no distinct notions of the preliminary 
branches of pneumatic science. The forcing pump was prob- 
ably suggested by the Egyptian wheel or noria, which was com- 
mon at that time, and which was a kind of chain pump, con- 
sisting of a number of earthen pots carried around by a wheel. 
In some of the machines the pots have a valve in the bottom 
which greatly reduces the resistance of operation ; this probably 
was the fundamental idea which led to the invention of the 
forcing pump. 

Till the seventeenth century, when in 1647 Pascal discovered 
the pressure of the atmosphere, the statement that " Nature 
abhors a vacuum " was accepted as good and sufficient cause 
for water rising into the vacuum produced by a pump. In 
1601 Giovanni Batista Delia Ponta describes an apparatus 
by which the condensation of steam in a closed vessel produces 
a vacuum, and may be used to suck up water from a lower level. 
To the Marquis of Worcester (1656) appears to be due the 
credit of making the first useful steam pump. It worked prob- 
ably like Delia Ponta's model, but with a pair of displacement 
chambers from which the water was displaced alternately. 
Thomas Savery obtained a patent in 1698 for a pumping 
apparatus on the same principle. 

In 1690 Denis Papin suggested that the condensation of 
steam should be employed to make a vacuum under a piston 

319 



320 SUBWAYS AND TUNNELS OF NEW YORK 

previously raised by the expansion of steam. Papin's was 
the earliest cylinder-and-piston steam engine, and was after- 
ward given practical shape in the atmospheric engine of New- 
comen. About 171 1 Newcomen's engine began to be intro- 
troduced for pumping mines; by 1725 these engines were in 
common use, and held their place for about three-quarters of 
a century. 

In 1782 Watt patented a double-action system of pumping 
engines. In 1781 Hornblower invented the compound engine; 
the compound engine was introduced widely by Woolf as a 
pumping engine in Cornish mines. But here it met a strong 
competitor in the high pressure single-cylinder engine of Tre- 
vithick, which had the advantage of greater simplicity of con- 
struction, and Woolf's engines fell into comparative disuse. 

The tendency of advance up to the present time in the types 
of pumping engines has been towards greater compactness 
and simplicity in design. This in a very marked degree has been 
the case in the type of pump now employed for general service, 
and sinking pumps in construction or mining operations. 

The development or evolution of the type of pump demanded 
by the conditions of modern tunnel construction is illustrated 
in the more compact and simple form of each succeeding design, 
from the massive atmospheric beam engines of Newcomen, 
the lighter be^am engines with higher steam pressure of Tre- 
vithick and Watt, the rotative or fly-wheel type of pumping 
engine, the duplex or double-cylinder direct-acting pump of 
the Worthington type, the single-cylinder direct-acting pump 
with outside valve gear, and culminating in the compact sim- 
plicity of the Cameron pump, in which the few moving parts 
are within the valve chest or cylinders and not subject to injury 
or derangement through extraneous causes. 

Before the introduction of the direct-acting pump in tunnel- 
ing or mining, the installation of the pumping plant was a serious 
feature of the work, the machinery being heavy and not of a 
form that was readily movable from place to place as the driv- 
ing or work advanced. The installation was kept at a fixed 
point, and involved the necessity of laying out and performing 



APPENDIX M 



321 



the driving in such a manner that sufficient grade for the 
proper flow of water through the drains could always be main- 
tained through gravity to the pumps. 

The maintenance of grades and drainage ditches to permit 
the flow of water to the pumps entailed the expenditure of 
much time and money. The introduction of the duplex direct- 




. 



"Cameron" Regular Pattern Piston Pump. 

acting pumps and the smaller fly-wheel pumps made it possible 
to do away, to a great extent, with drainage ditches, as the 
pumps could be moved as the exigencies of the work might 
require or the conditions permit. But in the confined space 
in headings or drifts, where there is a car track or where the 
excavated or other material is being hauled through, it is 
usually necessary to cut out or widen the drift to provide space 
for placing and housing pumps of this type. 

It is most important that all pumps having outside or exposed 



322 SUBWAYS AND TUNNELS OF NEW YORK 

moving gear of any sort should be properly and securely housed 
as a protection against derangement of the gear by material 
falling from the cars, blasted stone, material from the roof or 
sides, grit or sand or material floating up in the case of floods. 
To protect the exposed moving parts of the pumps, by provid- 
ing proper housing and cutting out the side of the drift if nec- 
essary to give the required width, may entail considerable 
outlay; but the susceptibility of the gear to derangement and 
the essential function of the pumps justify every means for 
their proper maintenance. The neglect of these precautionary 
measures has proven a costly experience to many engineers 
and contractors. The majority, if not all, of the contractors 
for building the cross-river tubes coming into New York, used 
the Cameron single-cylinder direct-acting pump for sinking 
and general service. 

The peculiar advantages of this pump are that it has no 
outside gear of any sort that may be deranged and put the pump 
out of service ; it requires no housing or protection, as its exposed 
parts are very much stronger and prove a better protection 
against injury than any housing that would be likely to be put 
over it. These pumps may be placed between the car track 
and the wall without widening of the drift or heading, or may 
be close to blasting operations without risk of injury. In 
the event of flooding or being drowned out the pump will start 
up no matter how deeply submerged, when the air pressure is 
turned on. There have been cases where this pump has been 
covered with broken rock and debris for weeks without interrupt- 
ing its efficient operation. 

Foundation Problems in New York City. C. M. Ripley. 
The gigantic increase in the erection of skyscrapers in the 
" Lower Broadway " section of New York City during the past 
few years has been made in the face of grave and increasing 
engineering difficulties. A study of the laying of the founda- 
tions for the Trust Company of America Building (see Fig. i), 
in the financial section of Wall Street, will bring out forcibly: 
(i) what these problems are, and (2) how the talent of engineer- 
ing contractors has been developed. Less than a dozen years 



APPENDIX M 



323 




" Cameron " Sinking Pump. 



324 



SUBWAYS AND TUNNELS OF NEW YORK 




Fig. 1. 



APPENDIX M 



325 



ago the following conditions would have been considered insur- 
mountable obstacles, making impossible the construction of a 
twenty-five story building on this site. 

As shown in the accompanying plan (Fig. 2) this building 
is situated between the present United States Trust Company 



WallSt. 









B 







B 


□ 


B 


B 


B 



— L*- 






g 






and the Mills buildings. Owing to the prevailing prices of 
Wall Street real estate, every inch of available space had to be 
utilized, with the result that the foundations of the new building 
practically " rub elbows " on either side with those of the old. 
It is not generally understood that, as we approach the south- 
ern end of Manhattan Island, the bed-rock slopes off lower 



326 



SUBWAYS AND TUNNELS OF NEW YORK 



and lower below the surface, so much so that at Wall Street it 
Is 80 feet below the curb and at the Battery between 90 and 100 
feet below. It might be mentioned in this connection that the 
rock appears at water line at about Fourteenth Street, and 
continues rising as we approach upper Manhattan, so that in 
building projects in this latter portion of the city, it is often 
necessary to blast away a miniature mountain before the site 

is even down to street level. 
It is due to this character- 
istic of New York's geological 
formation that the excavation 
for the great Pennsylvania 
Railroad depot has so often 
been termed a. veritable 
" quarry." • In these cases 
the foundations are supplied 
by nature. 

In striking contrast to 
such simple foundation prob- 
lems, we have the case in 
hand. Foundations have to 
be laid to bed-rock, through 
about 80 feet of quicksand 
and water-bearing strata, 
which is already heavily 
loaded by adjoining ten-story 
buildings. In digging, water 
and soft mud are encountered 
but a few feet below the street 
level, and were this soft muck 
pumped out or removed by 
any of the old-time methods, 
more of this fluid material would enter the excavation from 
either side, and the adjoining structures would settle and later 
collapse. The Foundation Company, to whom was entrusted 
the responsibility both of planning and doing this work, solved 
these problems by employing the pneumatic caisson process, 




Fig. 3. 



APPENDIX M 



327 



in conjunction with the Moran air lock, an invention of their 
vice-president, Mr. Daniel E. Moran, C.E. 

The principle of the air lock was used for the underpinning 
of the adjoining buildings as well as for the main part of the 
work. Cut No. 5 shows how work was begun even while the 
old building was being wrecked. Niches about 5 feet above 
the cellar floor, and 5 feet wide, were cut in the walls of the adjoin- 
ing buildings with Box electric and Ingersoll-Sergeant steam 
drills at intervals of about every 6 to 9 feet. These were 
carried downward through the old foundation, and through 



=^=G 



h^ 



r~ 



T=D 



fc=0 



SECTION^ 



SECTION^ 

Fig. 4. 



SECTION^ 



the sand under the foundation until the water line was struck. 
Then a 6-foot length of riveted steel pipe, 36 inches in diameter, 
was jacked down into the sand, thereby employing the weight 
of the building in constructing the new underpinning. A 
downward opening door was installed at the top of this length, 
a second length was bolted to the first, and then a second down- 
ward opening door was installed, completing the miniature 
air lock. As shown in Fig. 5, compressed air was supplied to 
the bottom chamber and the work pushed lower and lower 
through quicksand or hard pan, as successive lengths of pipe 
were bolted to the top, and material excavated. When rock 
was reached the entire cylinder was filled with concrete, the 



328 



SUBWAYS AND TUNNELS OF NEW YORK 



steel pipe remained, and when the steel beams were placed, as 
shown in the left side of Fig. 5, the underpinning at that point 
was completed. Twelve of these concrete cylinders support 
the wall of the Mills Building, and eleven that of the United 




Hard -Pan -s. 



Rock 



^ 



Awwwwwwwiww/wwmwAWW^ 



Fig. 5. 



States Trust Building, as shown by the circles in the shaded 
portion of Fig. 2. 

Twenty-seven concrete piers constitute the foundation work 
proper under the Trust Company of America Building. The 
remarkable speed with which these piers were sunk to bed- 
rock was made possible mainly from this one fact: The Moran 



APPENDIX M 329 

air lock allows the material excavated in caisson to be hoisted 
to the open air in one continuous haul, being handled but once 
in transferring from bottom caisson up to the dumping place, 
generally a truck. This feat was never possible with any other 
equipment until Mr. Moran took the lead and perfected his 
device shown in Fig. 4. 

The square and rectangular spaces shown in Fig. 2 give 
the location of the concrete piers on the site of the Trust Com- 
pany of America Building. In Fig. 6 is shown the 4-boom 
traveler derrick, which is equipped with four double-drum 
Lidgerwood hoisting engines, and which effectively covered 
the entire area. It served to place the caissons (one of which 
weighed 20 tons and was 14 by 31 by 8 feet high) at their proper 
location. It also hoisted men and material in and out of the 
twenty-seven working chambers. A typical caisson or work- 
ing chamber is shown in Fig. 3. 

Fig. 6 shows the Moran air lock in place, near the top of 
the picture. The man stooping down on the ground is the 
gage tender, who keeps the pressure steady for the con- 
venience of the men in the working chamber, and the man at the 
air lock communicates signals between the excavators and the 
engineers. 

Having a general knowledge of the difficulties and of the 
apparatus to be used, and having finished the description of 
the underpinning, we shall take up the method employed in 
sinking the twenty-seven great concrete piers through this 
soft soil to bed-rock without weakening the adjoining founda- 
tions. See Fig. 6. 

After the wooden caisson proper had been located accurately, 
the workmen with picks and shovels excavated inside the open 
topped frame, which gradually sank of its own weight. When 
it had sunk to water level, which was but 4 to 5 feet below the 
street, preparations were made to apply the compressed air 
as follows: The open top of the caisson was roofed over tem- 
porarily and the first 10-foot section of the steel collapsible 
working shaft was joined to the upper part of the caisson, as 
shown in Fig. 3. Section after section was added and then a 



330 



SUBWAYS AND TUNNELS OF NEW YOEK 



Moran air lock, as shown in Fig. 6. Then a section of tem- 
porary wooden cofferdam was built and fitted to the outside 
of the caisson, so as to extend its sides upward several feet. 
This was to act as a falsework for retaining the successive thin 




**5>g j^TTT"" 



Rock 



;Vv^itei''I.e ! ver 



-wv^ J p W \^ *%mm ^^^w\*\ < <^&tk&*\iii^ ^^^w^s^/^^s^^yvj^^jjg^g ^^ 



Fig. 6. 

layers of concrete dumped into the annular space inside the 
cofferdam and on the roof of the caisson surrounding the work- 
ing shaft, as will be noticed in the right hand side of section in 
Fig. 6. After the first io feet of concrete had hardened, a second 
cofferdam was fitted in a higher position, and the concreting 



APPENDIX M 331 

continued, the first cofferdam being later removed and used as 
the third. One gang of men and one mixer could move from 
cofferdam to cofferdam, applying a 2-foot layer in each, so that 
by the time they returned to the first one it was hardened enough 
to receive its next layer without distorting the sheeting; so 
nearly the full height and full weight of the finished pier was 
used to force the caisson down to its final resting place on bed- 
rock, as rapidly as the excavating could be done by the men 
inside. Alpha Portland cement was used on this job in a i to 
2 1 to 5 mixture. 

Referring again to Fig. 3, it will be noticed that the lower 
edges of the caisson sides are sharpened to form the " cutting 
edge " of the caisson, since they follow the level of the excava- 
tion and are pressed down by the great weight above. The 
contracting firm have prepared special 2-ton cast-iron weights, 
which can be piled on top of the concrete pier to further sink 
it, in case the " skin friction " on the sides is too great for the 
pier to sink of its own weight. 

During this process three eight-hour shifts of the laborers 
were digging out material in the caisson under a pressure of 
from 18 to 24 pounds per square inch. This material was 
shoveled into buckets and hoisted up through the working shaft 
and the air lock out to the atmosphere, all in one continuous 
lift. 

When bed-rock is reached, it is leveled off and, still under 
compressed air, the concrete is lowered into the caisson and 
rammed in place. The entire caisson is filled to the top, the 
temporary roof removed, and as the men retreat up the tube 
they unbolt and remove a section of the collapsible tubing and 
hoist it up for use in sinking another caisson. Gradually the 
entire space, previously used as a passage for men and material 
in and out of the working chamber or caisson, is filled with con- 
crete, thus making the pier one solid monolith of concrete from 
bed-rock to the column base. This is shown on the left side of 
Fig. 6. 

Referring again to plan view, Fig. 2, it is seen that these piers 
are sunk end to end with only a twelve-inch space between, and 



332 



SUBWAYS AND TUNNELS OF NEW YORK 



that the chain of piers around the entire site is made perfect 
by welding or bonding between the ends of each pier. This 
keeps the water from the surrounding soil from entering either 
the basement or sub-basement of the building. The method 
is as follows: In Fig. 7 will be seen the end faces of the two 
adjacent piers. The semi-octagonal groove shown in the faces 
was formed at the same time that the coffer-dam was put 
around the top of the caisson. The wooden falsework served as 
a " core," displacing the concrete from top to bottom of each end 
face of the piers. As soon as two adjacent caissons were ready 
to be welded or bonded the space bounded by A BAB was 
excavated. At the same time the laborers would tear off the 



F«S^SSS§3S3SSS^ 



fe$$S$^xxxmSS^m^^^^ 



^^^mw^^^-T 




^^^^S^^^^x 



boards AA, saw them into the shorter lengths BB, and nail 
them in position BB, as shown in dotted lines. The space 
between the piers thus had become octagonal in shape, and was 
carried down the few feet to the water level. The planks ABC 
were removed. A 4-foot length of steel cylinder 30 inches in 
diameter was placed in the opening, and the space between it 
and the surrounding concrete and boards BB was filled in with 
concrete and made air tight. An air lock was bolted to the 
top of this cylinder and the workmen excavated the material 
between A and B, tearing out all the lumber as they went down, 
and hoisting all the material to the surface except what was 
needed for completing the boards BB down to the top of the 
caisson. This octagonal well was then filled to the top with 
concrete under pressure, and the bond was complete. When 



APPENDIX M 



333 



these connections between piers were completed on the north, 
east and west borders of the building site, it was only necessary 
to make the bond with the foundation piers of the Wall Street 
Exchange building on the south (put in by the same contractor 



. •• ' 



, 



Curb-Level 



Water. Level 



WWffUJfff/f 




V^^fh 



Fig. 8. 



to bed-rock) in order to fully enclose the lot and prevent future 
flooding of the cellars, which reach to a depth of nearly 40 feet 
below the water level. It will be seen from Fig. 2 that this 
was done without expense of sinking a separate line of caissons 
on that side. 



334 



SUBWAYS AND TUNNELS OF NEW YORK 



Another advantage in this solid wall type of bonded founda- 
tion construction is that the piers in the center of the lot can 
generally be sunk without the expense of the compressed 
air method, for there is little danger of any water seeping 
in from the outside, and therefore of weakening the other 
buildings. 

At this stage of the job, the cellars can be safely dug, during 
which work the shoring of the neighboring building walls is 
done, as shown in Fig. 8. Fig. 9 illustrates the appearance 



y 



U.S. Trust 
Company 



Curb-Leveb 



Water-Level 



Mills 
Building 1 



Curb-Level^ 




^/Water-Level 



Fig. 9. 



when all the substructure is completed and the cellar made 
ready for installing engines and boilers. The general class of 
work of which this job is merely one branch is civil engineering 
in water or water-bearing strata, including mine shafts in wet 
or marshy lands, bridge piers, sea walls and tunnels. Com- 
pressed Air Magazine. 

Pneumatic Bridge Caissons in Great Britain. In a recent 
paper before the Institution of Engineers and Shipbuilders in 



APPENDIX M 335 

Scotland, Mr. Andrew S. Biggart described the operations in 
construction of a number of large bridges in Great Britain, 
in each of which undertakings the pneumatic caisson was a 
prominent feature, the work all executed by the firm of Sir 
William Arrol & Co. (Limited), Glasgow. 

The Clyde Bridge of the Caledonian Railway Company has 
five deck spans from 60 to 200 feet long, carrying at one end 
nine tracks and at the other end thirteen tracks. Each of the 
river piers has five cylindrical columns seated on brick piers, 
with rectangular pneumatic caisson foundations. The caissons 
are of steel and each of them had three 3^-foot air shafts and 
was built on a falsework extending across the river, which also 
provided for the delivery and storage of materials and for the 
subsequent erection of the superstructure. Two wooden trestle 
bents were erected on the falsework on opposite sides of each 
caisson, and each pair supported a pair of horizontal riveted steel 
plate girders forming gallows frames over the caissons. Four 
vertical rods, one near each corner of the caisson, were connected 
to the caisson, and, passing between the pair of girders, engaged 
saddles commanded by hydraulic jacks. The caisson was 
lowered by the jacks to water level, concreted and again lowered 
and released from the suspending rods and concreted until it 
took bearing on the river bed. During this operation the caisson 
was maintained in horizontal position by guys, but rose and fell 
with the tide. 

The bridge over the River Barrow, in the south of Ireland, 
has thirteen 140-foot fixed spans and one 215-foot swing span 
with 15 piers, each made with two 8-foot cylinders 26 feet apart 
on centers which had their bases extended to a diameter of 
from 10 to 15 feet. The lower portions of the cylinders were 
made with steel rings up to about the bottom of the river, and 
above that the cylinders were made with cast-iron rings. The 
cylinders were assembled on lateral extensions of a wooden 
falsework platform built across the river; the working chamber 
and the adjacent cylinder rings were lined with concrete and 
lowered to the river bottom by hydraulic jacks. The excava- 
tion in them was partly made by grabs, but in every case was 



336 SUBWAYS AND TUNNELS OF NEW YORK 

finished under pneumatic pressure. The upper rings were added, 
and concreting between the air shaft and the rings was continued 
as the cylinders sank. Although they were carried down to 
an extreme depth of 120 feet below high water level, the pres- 
sure was reduced by special measures to a maximum of 45 
pounds per square inch. This was mainly accomplished by 
the use of ejectors operated by compressed air to remove the 
water which came in under the cutting edge. The usual pre- 
cautions were taken for the safety of the workmen by reducing 
the hours of work, restricting the speed of their exit, and pro- 
viding warm refreshments and rest for them immediately after 
emerging from pressure. After the working chamber was con- 
creted the air pressure was maintained on it for several days. 
The top ring of the cylinder was made of special depth to bring 
the upper edge to the required level. The cost of excavation 
at the maximum depth reached $200.00 per cubic yard. 

The Suir Bridge, near the Barrow Bridge, carries the same 
single track railway on nine spans of about 140 feet, with cylin- 
der piers similar to those of the Barrow Bridge, but not sunk 
to so great a depth. When one of the cylinders had sunk to 
a depth of 70 feet below the river bottom, and was subjected to 
a pressure of 32 pounds, one of the cast-iron rings just below the 
bed of the river burst, under a tensile stress of about 1000 pounds 
per square inch. The casting had been satisfactorily tested 
before acceptance, and pieces of it were tested after the accident 
and gave results up to the specifications without disclosing any 
flaw in the metal. No explanation has been offered for the 
break. A wooden cofferdam was built around the top of the 
cylinder and pumped out, and the broken ring was removed 
and replaced by a new one, and a concentric steel shaft 3 feet 
in diameter was set in it and extended down through the con- 
crete lining to a point 5 feet below the upper end of the steel 
portion of the cylinder. The lower 9 feet of this shaft was then 
grouted to the concrete filling, the air-lock was placed on top 
of it, and sinking successfully completed. 

The Black Friars Bridge over the Thames, in London, has 
five flat steel arch spans of 155 to 185 feet, which were recently 



APPENDIX M 337 

enlarged by extending the width of the structure from 43 to 73 
feet. This involved a corresponding extension of 30 feet at one 
end of all the piers, which were of masonry and were each sup- 
ported on several rectangular pneumatic caissons and one 
triangular caisson forming a cut-water at the upstream end, 
where the extension was made. Pile falsework platforms were 
made enclosing the up-stream ends of the piers and extending 
10 feet beyond it up-stream. Steel pneumatic caissons for the 
foundations of the pier extensions, with a semicircular cut- 
water on the up-stream end and a recess on the down-stream 
end to fit the nose of the old cut-water, were assembled and 
riveted on the falsework. The downstream end of the caisson 
did not, however, reach entirely to the main part of the old 
pier, but left a narrow gap there on each side of the down- 
stream end of the old cut- water. The caissons were assembled 
by steel stiff-leg derricks installed on the falsework platforms. 
A timber trestle was built parallel to the axis of the caisson on 
each side of it on the deck of the falsework platforms, and two 
pairs of steel-plate girders were seated on them, one at each end 
of the caissons, provided with vertical rods and hydraulic jacks 
by which the caisson was slightly lifted, while the supports under 
it were removed. Concrete was filled into the cutting edge 
and on the roof of the caisson and it was lowered to the bottom 
of the river, the sides being carried up by a temporary steel 
cofferdam continuous with them and heavily braced with interior 
timbers as it descended. The caissons were sunk just below 
the bottom of the river and the side spaces between the old 
and new caissons were enclosed by wooden cofferdams which 
were pumped out, allowing them to be excavated and concreted. 
After one of the caissons had been lowered a few feet below 
high water, and was still suspended from the overhead girders, 
the hydraulic jack which supported one of its corners was pre- 
maturely exhausted, relieving the opposite diagonal jack of its 
load, throwing the entire 2 50- ton weight of the caisson on the 
remaining two jacks, and settling the piles under one of them a 
few inches. This movement caused the caisson to swing and 
the falsework to collapse, precipitating the caisson to the bottom 



338 SUBWAYS AND TUNNELS OF NEW YORK 

of the river. The caisson was then braced by interior cross- 
girders and web plate brackets, and the point was lifted by 
hydraulic jacks operating bars suspended from two box girders 
braced together on the falsework platform. The caisson was 
then moved to proper position on sliding bearings, and was 
sunk in the usual manner. Compressed Air Magazine. 

Pit Sinking through Frozen Quicksand. Mr. E. Seymour 
Wood recently read a paper before the North of England Institu- 
tion of Mining Engineers describing a remarkable feat of shaft 
sinking through quicksand by the aid of the freezing process. 
The coal mine is located close to the east coast of the county 
of Durham, which lies south of Newcastle-on-the-Tyne. 

The difficulties of sinking shafts in the East Durham dis- 
trict arise from the occurrence of magnesian limestone and 
underlying yellow sands, the latter being usually found as a 
quicksand, and both of these strata contain large quantities 
of water. At Dawdon, the magnesian limestone is 356 feet 
thick, and the yellow sand 92 feet thick. The limestone, as is 
usual, is full of gullets, giving off large quantities of water. Some 
of these gullets are connected with the sea, the water issuing 
from them being salt. The question was therefore con- 
sidered whether to erect additional pumping plant or to carry 
out the sinking of the shafts through the sands in a frozen state. 
It was decided to adopt the freezing process. Accordingly, 
the shafts, each enclosed in a wooden shed, were handed over 
to the contractors, Messrs. Gebhardt and Koenig, Nordhausen, 
in April, 1903. This firm undertook the freezing of the ground 
through which the two shafts were to be sunk, and also the 
adjoining ground, to such an extent as to enable the owners 
of the colliery to carry out their sinking arrangements with- 
out the aid of pumps, until each shaft was sunk to a depth of 
484 feet from the surface, and to establish and maintain a 
solid wall of ice around each shaft, so long as should be necessary 
for the purpose of sinking. Twenty-eight bore holes were marked 
off in a circle 30 feet in diameter surrounding the shafts, and 
were bored to a depth of 484 feet. After the whole of the 
freezing tubes were inserted, they were connected to the inner 



APPENDIX M 339 

and outer collectors, for the circulation of brine. The length 
of time required to form the ice wall at the Castlereagh shaft 
was 185 days. The ice wall was maintained 353 days, and the 
total time of freezing was 538 days. The sand was struck at a 
depth of 371 feet and found to be frozen hard. In the shaft 
bottom the frozen sand was so hard that blasting had to be 
continued throughout the deposits. The temperature of the 
frozen sand at the bottom of the pit was i4°C. (+6° F.). The 
thawing of the frozen ground was accomplished by circulating 
warm brine through the freezing tubes. Once through the 
frozen sand the progress of the operations was very brisk. 
Compressed Air Magazine. 



APPENDIX N 



ENGINEERING DATA 



CUBIC FEET OF FREE AIR REQUIRED TO RUN ONE DRILL OF 
THE SIZE AND AT THE PRESSURE STATED BELOW 



1 01 








Size and Cylinder Diameter of 


Drill. 








^ O 


A35 


A3 2 


B 


C 


D 


D 


D 


E 


P 


F 


G 


H 


H 9 


OS 


2" 




if/ 

* 2 


2!" 


3" 


-, it/ 

OS 


3fV' 


3i" 


iff 
02 


■ySff 

08 


4i" 


5" 


sV 


6o 


5o 


60 


68 


82 


90 


95 


97 


IOO 


108 


113 


130 


150 


164 


70 


56 


68 


77 


93 


I02 


108 


no 


113 


124 


129 


147 


170 


181 


80 


63 


76 


86 


104 


114 


120 


123 


127 


131 


143 


164 


190 


207 


90 


70 


84 


95 


115 


126 


133 


136 


141 


152 


159 


182 


2IO 


230 


100 


77 


92 


104 


126 


138 


146 


149 


154 


166 


174 


199 


240 


252 



340 



APPENDIX N 



341 



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rl-iOO t^00 00 m <N to ^ vO 00 


tOtOtOtOtOtOt't^^'tTt't 


to 


OOOt^OOO-^J-csOoOO O 
J^f^OO OO M cs to rt- ^t IO N 00 


CS M <N CS cotOtOtOtOtOtOtOtO 


<N 


VOCN00 lOOO M N M 00 f^t^ 

0000 OOO M M <N (N to to t)- io 


MHMM<NCS<NCSCSCN<NCSM 


M 


to N o •^■t^o too Ots *>. to 

OOMMMCSMCSCNCOtO'^- 




•J9 a; 

3A 

apt 


oqy 


0) 

ft. 


ooooooooooooo 
oooooooooooo 
oooooooooooo 

m cs co^^O^OO OO ts io 

MUM 



o 






-a 
3 



o 

o 



3 



w 



u 

** G 

<u .- 

«+H IO 

O v 

8 § 

& .G 



in o 

c 

00 O 

co-Z3 
O xj 

>, ° 

*j « 

« £° 

.a > 

3 - 
°^ 

O M 
M 3 



>» 


-! 


a 


O 






•i-j 


<1) 


3 


> 


S 


(J 




rt 






00 


<U 


CO 


-a 


O 


-HJ 








U, 


(fl 


O 



V M 

T3 O 
3 W 



en -<-> 

*H co 






6 
o 



On S, 




O * 

O >H 


O 13 








^j ou 


K X 3 




** G S 


>% O O 




co S -^ 


13 .S a 




e co 
oi C <u 


^ <U o 




drill 
place 
and 1 


U L, 00 




U C3 ^_, 

« 3 tj 




Co" 




« en 


tn en 




.ti u B 




tO*C o 


CO <U M 






a-o 




CU [fl fl> 




<*J •*-< Ih 


t of fre 
o pound 
ating th< 




e factor 
which is 
such as i 


C 00 «H 




amou 
ure of 
en ope 




"5 ~ tn 


4-1 

3 


„_) .*-> in 
co 3 g 


r-, w 'G 

aj cn > 

rG V > 


x5 G c; 


ired t 
agepr 
e find 


a 

M 


lso fin 
ir per 
pipe li 


3 Mfe 
o; co o 


M 


CO co 

0) <u CJ 


& *j ^ 






CU 


CU 


> *j 


XAMPLE. 

drills air 
rom pag 


H 

o 


O <U 0) 
o cu X) 

^H <-M 
CO ^ 




rom 
ubic 
mus 


W c fe 


CJ 


fa W J3 






CS CJ 


CU ^3 


00 -g 
co ^ 


J3 


3 


-tJ 


u 



342 



SUBWAYS AND TUNNELS OF NEW YORK 



LOSS OF PRESSURE IN POUNDS BY FRICTION IN TRANS 

Initial Air Pressure 





Delivery in Cubic Feet of 


0) 


9.84 


14-73 


19.64 


24.60 


29.45 


34-44 39-35 


49.20 


58.90 


68.6 


78.6 


88.4 


98.4 


CO 


Equivalent Delivery in Cubic 




so 


75 


100 


125 


150 


175 


200 


250 


300 


350 


400 


450 


500 


I 


18.24 
5.06 

i-95 
0.42 
0.13 
0.05 


























t! 


n-34 
4-33 
o-9S 
0. 29 

O.II 

0.05 


20. 16 

7-79 
1.69 
0.52 
0.19 
0.08 
0.04 






















T + 


12.23 
2.65 
0.81 
0.30 
0.13 

0.07 

0.03 


17-53 
3.80 
1. 16 
0.44 
0. 19 
0. 09 


















2 


5-17 
I- 58 

0-59 
O. 20 
11 


6.77 
2.O9 
O.78 
O.36 
O.I7 
O.O9 
O.OO 
0.02 
O.OI 


10.61 

3- 2 4 
1 . 22 

0-55 
0. 27 

0.15 
0.08 
0.03 

O.OI 


15. 20 

4-65 

1.78 

0.78 
0.38 

0.21 

O. 12 
O.OS 
0.02 
O.OI 










3. 

32 

4 

4* 

5 
6 


6.31 

2-37 
1 .07 

o-53 
0. 29 
0.17 
0.06 
0.03 

O.OI 


8.28 
3." 

1 .40 
0.69 
0. 9 
0. 22 
0.08 
0.04 

O.OI 


10.47 

3-94 
1.77 
0.88 
0.48 
0.28 
0. 11 
0.05 
0.02 

O.OI 


4.88 

2.20 
1.08 






0.050.07 

0.03 O CtA 
6 


0.60 








0.34 

0.14 

0. 06 












O.OI 


7 
8 
























0.03 

O.OI 


9 
10 










































12 




























14 




























t6 























































Initial Air Pressure 





















Delivery in Cubic Feet of 


** 


7-74 


11.3 


IS-2 


19.4 


23.2 


27.2 


31.0 


38.7 


46.5 


54-2 


62.0 


69.7 


77.4 


Equivalent Delivery in Cubic 




50 


75 


100 


125 


150 


175 


200 


250 


300 


350 


400 


450 500 


I 


I4-3I 
3 96 
i-53 
o-33 

O.IO 

0.03 

O.OI 




























8.46 
3.26 
O. 71 
O. 21 
O.08 
O.O3 
O.OI 


1531 
592 

1.28 

0-39 
0. 14 
0.06 
0.03 
0.02 

O.OI 






















9.64 

2.09 
0.64 
0. 24 
0. II 
0.05 
0.03 

O.OI 


13-79 
2.99 

0.91 
0-34 
015 
0.07 
0.04 
0.02 
.0.01 
















2 


4.09 


K.-iA 


8.32 

2-54 
O.96 

0-43 
O. 21 
O. 12 
O.07 
O 02 


12.01 
3 67 
1.38 
0.62 
0.30 
17 
0.09 
0.03 

O.OI 








,1 
2 2 

3 

3* 

4 

1 1 


1.25 1.63 
0.47 0.61 
0.21 0.27 
0. 100. 13 
0.06 0.07 

O 03 <~> csa 


4-99 
1.88 
0.84 
0.41 
0.23 
0.13 
0.05 
0.02 

O.OI 


6-53 
2-45 
1 . 11 

o-54 
0.30 
0. 17 
0.06 
0.03 

O.OI 


8.25 
313 

1.40 
0.69 

0.38 

O. 22 
O.08 
O.O4 
O.OI 


10.81 

i-73 
0.85 
0.47 
0.27 


5 
6 










O.OI 


O.OI 


7 
8 












O.OI 


0.05 
02 
















9 
10 




















01 




























12 




























14 




























t6 

























































For longer or shorter pipes the friction loss is proportional to the length, i. c, 



APPENDIX N 



343 



MISSION OF AIR THROUGH PIPES 1000 FEET LONG. 
60 Pounds Gage. 



Compressed Air Per Minute. 



118. 1 137-5 156.6 176.5 196.4 294-5 393-7 492 589 686 786 884 984 



.2-S 

o 

4J j-. 



Feet of Free Air Per Minute. 



600 700 800 900 ; 1000 1500 2000 2500 3000 3500 4000 4500 5000 



03 9 
174 
56 2 
871 
490 
19 o 
09 o 

04 o 



52 
29 

12 
17 

67 
27 
12 
06 

03 
02 



57 

75 

52 

87 

34 

15 

08 

04 

030 

01 o 



8-77 
4-33 
2.40 

37 
54 
24 
12 
0.06 
0.04 
0.02 
0.01 



965 

5-51 
2. 16 
0.98 
0.41 
0.27 
o. 16 
0.06 

0.03 

O.OI 



I 

li 
I* 



2h 



32 

4 

4l 
5 
6 

7 
8 

9 
10 
12 

14 
16 



80 Pounds Gage. 



Compressed Air Per Minute. 


















92.9 


108.2 


124.0 


139.5 


152 


232 


310 


387 


465 


542 


620 


697 J 774 


.!7<u 

0H.C 


Feet of Free Air Per Minute. 




trx 


600 


700 


800 


900 


IOOO 


1500 


2000 


2500 


3000 


3500 


4000 


4500 


5000 






























1 




























t! 




























2 






















































a* 

3 

3\ 

4 

4 

5 
6 

7 
8 

9 

10 
12 


5.6i 

2.46 
1 . 22 


7.46 

3-37 
1.66 

O f»5 


9.86 
4.42 
2.18 
1. 19 

0.69 
0. 27 

O. 12 

O.06 
O.O3 
0.02 
O.OI 






















5.61 

2.77 

i-54 
0.88 

o-34 
0.15 
0.08 
0.04 
0.02 

O.OI 


6.64 

3 29 

1.82 
1 .04 
0.40 
0.18 
0.09 
0.05 
0.03 

O.OI 


1541 

7.62 
4.24 
2.43 

o-95 
0.43 
0. 22 
0. 12 
0.06 
0.02 

O.OI 
















13.62 

7.58 

432 

1 .69 

0.77 

o-39 
0. 21 
0. 12 
0.04 
0.02 

O.OI 














0.68 


11.79 

6.88 
2.64 
1. 19 
0.60 

o-33 
0. 19 
0.07 
0.03 












O JQO.tJ 


9.72 

3-79 
i-73 
0.87 
0.48 
0.28 

O.II 

0.0? 


13-25 
5-27 
2-35 
1. 19 
0.65 
o.37 
015 
0.06 
0.03 








6 * 

O.I5 
0.06 
0.03 
0.02 

O.OI 


O. 20 
O.O9 
O.O4 
0.02 
O.OI 


6.78 
3°7 
i-55 
0.85 
0.49 
0. 19 


8-54 
3.89 
I.97 
I.08 
O.66 
O. 2< 


io-55 

4-79 
2.46 

i-33 
0.77 
0. 1.0 






0.09 0. ill 0. id. 


14 
t6 












O.OI 0.02 


0.04 


O.05 0.07 

























for 500 feet one-half of the above; for 4000 feet four times the above, etc. 



344 



SUBWAYS AND TUNNELS OF NEW YORK 



LOSS OF PRESSURE IN POUNDS BY FRICTION IN 

Initial Air Pressure 





Delivery in Cubic Feet of 


4> 


6.41 


9.61 


12.81 


15.81 


19.22 


22.39 


25.62 


31.62 


38.44 


44.78 


51.24 


57.65 


63.24 




Equivalent Delivery in Cubic 




50 


75 


100 


125 


150 


175 


200 


250 


300 


350 


400 


450 


500 


1 


11.89 

3-29 
1.28 
0.27 
0.08 
0.03 
0.01 


























Tl 


7.42 
2.87 
O.62 
O.19 
O.07 
O.03 
O.OI 


13.20 

LIS 

0.34 

0.12 

0.05 

0.02 

O.OI 






















I* 

2 


7-75 
1.68 
0.52 
0.19 
0.08 
0.04 
0.02 

O.OI 


11.42 

2.48 

0.76 
0.29 

0.13 

0.06 

0.03 

0.02 

O.OI 


















3-36 
1.03 

o-39 
0.17 

0.09 
04 
0.03 

O.OI 


4.43 
1.36 
0.51 
0.23 

0.12 
0.06 
0.04 
0.02 

O.OI 


6.72 
2.06 
0.77 

o.35 
0.17 
0.09 
0.05 
0.02 

O.OI 


9-95 
3-°4 
1. 14 
0.51 
0.25 
0.14 
0.08 
0.03 

O.OI 


13-41 
4.11 

i-54 
0.69 

0.34 
0.19 
0.1 1 
0.04 
0.02 

O.OI 








2* 

3 

32 

4 

4* 
5 
-6 


5.40 

2.06 
0.92 

0.45 
0.25 

o.is 
0.05 
0.03 

O.OI 


6.85 

2.57 
1. 16 

0.57 
0.32 
0.18 

0.07 

0.03 

0.02 
. . .01 


8.21 

3.08 

i-39 
0.68 
0.38 
0.22 












0.08 


7 
8 










0.04 
0.02 














9 
10 




















O.OI 




























12 




























14 
t6 



















































































Initial Air Pressure 





Delivery in Cubic Feet of 




5.26 


7.89 


10.51 


13.15 


15.79 18.41 


21.05 26.30 


31.58 


36.81 

1 


42.10 


47.30 


52.60 




Equivalent Delivery in Cubic 




50 


75 

22.20 
6.07 

2-37 
O.51 
O.16 
O.06 
O.03 
O.OI 


100 


125 


150 


175 


200 


250 


300 


350 


400 


450 


500 


I 


9.88 
2.70 

1. 05 
0.23 

0.07 
0.03 

O.OI 


39-50 

10.82 
4.22 
0.91 

0.28 

O.IO 

0.05 

0.02 

O.OI 


















t! 


16.88 
6.58 

1.42 

0.43 

0.16 
0.07 
0.04 
0.02 

O.OI 


24-33 
9-47 
2.04 
0.63 
0.23 
0.1 1 

0.05 
0.03 

0.02 

O.OI 


33.05 

12.90 

2.78 
0.85 
0.32 

0.14 
0.07 
0.04 
0.02 

O.OI 
















2 

3 

52 

4 
1 1 


16.84 

3-63 
I. II 
O.42 
O.I9 
O.O9 
0.05 
O.O3 
O.OI 


26.30 

5.68 

1.73 
0.65 

0.29 

0.15 
0.08 
0.0s 

0.02 

O.OI 


37-90 
8.18 
2.51 
0.94 

0.42 
0.21 
0.12 
0.07 

0.03 

O.OI 










11.08 

3-39 
1.27 
0.58 
0.28 
0.16 
0.09 
0.04 
0.02 

O.OI 


14.51 
4.44 

1.67 

0.75 
0.37 

0.21 
0.12 

0.05 

0.02 

O.OI 


18.38 
5.61 

2. II 

0.95 

0.47 
O.26 

o.is 
0.06 
0.03 

O.OI 
O.OI 


22.68 

6.95 

2.61 

1. 18 
0.58 
0.32 
0.18 


5 
6 












0.07 

0.03 

0.02 


7 
8 
























9 
10 














1 




O.OI 



























12 




























14 
t6 














































































■ 





For longer or shorter pipes the friction loss is proportional to the length— i.e., 



APPENDIX N 



345 



TRANSMISSION OF AIR THROUGH PIPES 1000 FEET LONG 
ioo Pounds Gage. 



Compressed Air per Minute. 




















76.88 


89.56 102. 5 


115.3 126.5 


192.2 


1 

256.2 316.2 j 384.4 


447.8 512.4 576.5 


632.4 


0hJ3 


Feet of Free Air per Minute. 





600 


700 


800 


900 


1000 


1500 


2000 


2500 


3000 


3500 


4000 


4500 


5000 




























I 


























il 


























1^ 




























* 2 
2 


12.21 


























2* 


4.58 
2.14 
1.03 
o.57 
o-33 
0.12 
0.05 
0.03 
0.02 

O.OI 


6.I9 
2.70 


8.13 

a. 67 


10.23 
4.64 

2.29 
1.27 
0.76 

0.28 
0.13 

0.06 
0.04 
0.02 

O.OI 


12.39 
5.60 
2.76 
1.23 
0.88 
0.34 

0.16 

0.08 

0.04 

0.03 

O.OI 


















* 2 

3 

zh 

4 

Ah 

5 
6 

7 
8 

9 
10 
12 


12.81 
















I.38 I.8l 

0.77 1.00 

0.44 O. C7 


6.68 

3-5i 
2.03 
0.78 
0.36 
0.18 
0.09 
0.05 
0.02 

O.OI 


n-35 
6.61 
3.62 
1.41 
0.67 

o-33 
0.18 

O.IO 

0.04 
0.02 

O.OI 














9-56 

5-5i 
2.14 
0.97 
0.49 
0.27 
0.16 
0.06 
0.03 

O.OI 


14.04 

8.11 
3.16 
1.44 
0.76 

o-39 
0.23 
0.09 
0.04 
0.02 










10.95 
4.26 

i-93 
0.98 

o.53 
0.31 
0.12 
0.05 
0.03 


14.48 
5-59 
2-55 
1.30 
0.72 
0.41 
0.16 






O.I7 
O.07 
O.O4 
0.02 
O.OI 


0.22 

O.IO 

0.05 
0.03 

0.02 

O.OI 


7.04 

3-22 
I.84 
O.89 
O.52 

0.?T 


8.51 
3-88 
I.98 
I.07 
O.63 
0.25 

O.II 

0.06 






0.07 0.09 
0.04. 0.0c 


14 
16 



























125 Pounds Gage. 



Compressed Air per Minute. 




















63.20 


73.70 84.20! 94.70] 105. 1 

1 1 


157.9 210.5 


263.0 


315.8 


368.1 


422.0 


473.0 


526.0 


Q. w 


Feet of Free Air per Minute. 




35 


600 


700 


800 


900 


1000 


1500 


2000 


2500 


3000 


3500 


4000 


1 
4500 | 5000 
























1 


























ii 
























1 


ii 




























2 


10.00 


13.60 T7.8o 






















2h 


3-76 
1.69 
0.84 
0.46 
0.27 

O.IO 

0.05 
0.02 

O.OI 
O.OI 


5- 11 
2.31 
1. 14 
0.63 
0.36 
0.14 
0.06 
0.03 
0.02 

O.OI 


6.68 
3.01 
1.49 
0.83 
0.47 
0.18 
0.08 
0.04 
0.02 

O.OI 
O.OI 


8.45 
3.81 

1.88 
1.04 
0.60 
0.23 

O.II 

0.05 
0.03 
0.02 

O.OI 


10.42 

4.71 
2.32 

1.29 

0.74 
0.29 
0.13 

0.07 
0.04 
0.02 

O.OI 


23.48 
10.59 

5-23 

2.90 

1.65 

0.64 
0.29 

0.15 
0.08 
0.05 

0.02 
















3 
3h 

4 

Ah 
5 
6 

7 
8 

9 

10 
12 


18.81 


29.40 

14.52 
8.05 

4.60 

1.80 
0.82 

0.41 

0.23 
0.13 
0.05 

0.02 

O.OI 












9-30 

5-15 
2.94 

1. 15 
0.52 
0.26 
0.15 
0.08 
0.03 


20.90 

n-59 
6.63 

2-59 
1. 18 
0.60 

o.33 
0.19 
0.07 
0.03 
0.02 


28.51 

15.78 

9.01 

3-53 
1.61 
0.81 

o.45 
0.26 

O.IO 

0.04 
0.02 








20.61 
11. 
4.61 
2.19 
1.06 
0.58 

0.34 
0.13 

0.06 
0.03 


26.10 
14.90 

5.83 
2.65 

i-34 
o.73 
0.43 
0.17 
0.08 
0.04 


32.20 

18.45 
7.20 

3-27 
1.65 
0.90 

°-53 
0.21 

O.IO 

0.05 






0.01 0.02 


14 
16 














O.OI 

















for 500 feet one-half of the above; for 4000 feet four times the above, etc. 



346 



SUBWAYS AND TUNNELS OF NEW YORK 



HORSE-POWER DEVELOPED IN COMPRESSING ONE CUBIC FOOT 
OF FREE AIR FROM ATMOSPHERIC PRESSURE (14.7 POUNDS) 
TO VARIOUS GAGE PRESSURES 

Initial Temperature of the Air in Each Cylinder Taken as 6o° F 
(Jacket Cooling not Considered). 



Gage 


Isothermal 


Adiabatic Compression. 










Pressure. 


Compression. 


One Stage. Two 


Stage. 


Three Stage. 


Four Stage. 


IO 


■0332 


•03S8 










20 


•055I 


.0623 










30 


.0713 


.0842 










40 


.0842 


.1026 










50 


.0950 


.1187 










60 


.1042 


•1331 










70 


.1122 


.1465 


128 




122 


.119 


80 


.1194 


.158S 


137 




131 


.127 


QO 


.1258 


.1695 


146 




139 


•135 


IOO 


•1317 


.1800 


154 




146 


.142 


125 


•1443 


. 2036 


171 




161 


•157 


150 


•1549 


.2244 


186 




174 


.169 


200 


.1719 


.2600 


2IO 




196 


.190 


300 


.1964 


.3164 


247 




229 


.220 


400 


.2141 


.3613 


276 




253 


.242 


500 


.2279 


.3889 


299 




272 


.260 


600 


•2393 


.4318 


318 




288 ■ 


•2 75 


700 


.2489 


.4608 


335 




302 


.289 


800 


•2573 


.4873 


349 




314 


.299 


900 


.2649 


• 5 XI 4 


363 




325 


.310 


IOOO 


. 2720 


•5337 


■375 




335 


.318 


1200 


.2829 


•5742 


397 




•353 


•333 


1400 


.2924 


.6102 


.414 




.368 


•347 


1600 


.3012 


.6427 


•432 




.381 


•359 


1800 


.3087 


.6724 


•447 




•393 


•369 


2000 


•3154 


.7003 


.460 




•403 


•379 



Note. The above values are for sea-level conditions only. 

GLOBE VALVES, TEES, AND ELBOWS 

The reduction of pressure produced by globe valves is the same as that caused 

by the following additional lengths of straight pipe, as calculated by the formula : 

1 14X diameter of pipe 



Additional length of pipe= 



Diameter of pipe \ 1 1 - 
Additional length 



1 + (3 .6 -:- diameter) 
3 3h 4 5 



6 inches 



2 
7 


4 
8 


7 
10 


10 

12 


13 
15 


16 
18 


20 
20 


28 
22 


36 feet 
24 inches 



44 53 7° 88 115 143 162 181 200 feet 
The reduction of pressure produced by elbows and tees is equal to two-thirds 
of that caused by globe valves. The following are tne additional lengths of straight 
pipe to be taken into account for elbows and tees. For globe valves multiply by f : 
Diameter of pipe \ ii| 2 i\ 2> z\ 4 5 6 inches 
Additional length J 2 3 



5 
10 



7 
12 



9 
15 



11 
18 



13 

20 



19 

22 



24 feet 
24 inches 



30 35 47 59 77 96 108 120 134 feet 
These additional lengths of pipe for globe valves, elbows, and tees must be 
added in each case to the actual length of straight pipe. Thus a 6-inch pipe, 
500 feet long, with 1 globe valve, 2 elbows and 3 tees, would be equivalent to a 
straight pipe 500+36+ (2X 24) + (3X 24^656 feet long. 



APPENDIX N 



347 



LOSS OF WORK DUE TO HEAT IN COMPRESSING AIR FROM 
ATMOSPHERIC PRESSURE TO VARIOUS GAGE PRESSURES BY 
SIMPLE AND COMPOUND COMPRESSION 

Air in Each Cylinder; Initial Temperature 6o° F. 





One Stage. 


1 
Two Stage. 


Three Stage. 


1 

Four Stage. 


6 
u 

3 
a> 

ID 
U 


Percentage of Work Lost in Terms of 


Ah 


















bo 
a 

a 


Iso- 
thermal 

Com- 
pression. 


Adia- 
batic 
Com- 
pression. 


Iso- 
thermal 

Com- 
pression. 


Adia- 
batic 
Com- 
pression. 


Iso- 
thermal 

Com- 
pression. 


Adia- 
batic 
Com- 
pression. 


Iso- 
thermal 

Com- 
pression. 


Adia- 
batic 
Com- 
pression. 


6o 


29.9 


23.O 


13-4 


11. 8 


8.6 


7-9 


4-7 


4-5 


70 


30.6 


23-4 


14. 1 


12.4 


8-7 


8.0 


6.1 


5-7 


8o 


32.7 


24.6 


14.7 


12.8 


9-7 


8-9 


6.4 


6.0 


90 


34-7 


25-8 


16. 1 


13-8 


10.5 


95 


7-3 


6.8 


100 


36.7 


26.8 


16.9 


14-5 


10.9 


9.8 


7-8 


7-3 


125 


41. 1 


29.2 


18.5 


15.6 


11. 6 


10.4 


8.8 


8.1 


150 


44.8 


30.9 


20. 1 


16.7 


12.3 


10.9 


9.1 


8.4 


200 


51.2 


33-9 


22.2 


18. 1 


14.0 


12.3 


10. s 


9-5 


300 


61.2 


37-9 


25 -7 


20.5 


16.6 


14. 2 


12.0 


10.7 


400 


68.7 


40.7 


28.9 


22 .4 


18.2 


15-4 


13- 1 


11 -5 


500 


70.6 


41.4 


31.2 


23.8 


19-3 


16.2 


14. 1 


12.3 


600 


80.4 


44-5 


32.8 


24-7 


20.4 


16.9 


14.9 


13.0 


700 


85.0 


46.0 


34-6 


25-7 

1 


21.3 


17.6 


16. 1 


13-8 


800 


89-5 


47.2 


35-7 


26.3 


22.0 


18. 1 


16.2 


13-9 


900 


93-0 


48.2 


37-i 


27.0 


22.6 


18.5 


16.6 


14.4 


1000 


96.1 


49.0 


37-9 


27-5 


23.2 


18.8 


16.9 


14-5 


1200 


102.8 


50-7 


403 


28.8 


24.8 


19.9 


17.7 


150 


1400 


108.6 


52.0 


4i -5 


29-3 


25-9 


20.5 


18.6 


15-7 


1600 


H3-4 


53-i 


43 5 


30-3 


26.5 


20.9 


19. 2 


16. 1 


1800 


H7-5 


54-o 


44-8 


31.0 


27-3 


21 .2 


19.6 


16.4 


2000 


122.0 


55-o 


45-8 


31-4 


27-5 


21.5 


19.9 


16.5 



348 



SUBWAYS AND TUNNELS OF NEW YORK 



FLOW OF AIR THROUGH AN ORIFICE, 

In Cubic Feet of Free Air per Minute, Flowing from a Round Hole in 
Receiver into the Atmosphere 



eter 

ifice, 

ties. 














Receiver Gage Pressure. 








Diam 

of Or 

Inc 


2 lbs. 


5 lbs. 


10 lbs. 


15 lbs. 


20 lbs. 


25 lbs. 


30 lbs. 35 lbs. 


40 lbs. 


1 

64 


■038 


•0597 


.0842 


.103 


.119 


•133 


•156 173 


.19 


l 

32 


•153 


.242 


•342 


.418 




485 




54 


.632 


•71 


•77 


1 
T8~ 


.647 




•965 


1.36 


1.67 


1 


93 


2 


16 


2.52 


2.8o 


3-07 


1 

8 


2-435 


3 


.86 


5 


45 


6.65 


7 


7 


8 


6 


10. 


II .2 


12.27 


1 
4 


9-74 


15 


.40 


21 


8 


26.70 


30 


8 


34 


5 


40. 


44-7 


49.09 


1 

8 


21-95 


34 


.60 


49 




60. 


69 




77 




QO. 


100. 


110.45 


JL 


39.00 


61 


60 


87 




107. 


123. 




138 




l6l. 


179. 


196.35 


5 

8 


61 .00 


96 


50 


136 




167. 


193 




216 




252. 


280. 


306 . 80 


4 


87.60 


133 




196 




240. 


277 




310 




362. 


400. 


441-79 


t 


119.50 


189 




267 




326. 


378 




422 




493- 


55o. 


601 .32 


i 


156. 


247 




35o 




427. 


494. 




55o 




645- 


715. 


78S-40 


ii 


242. 


384 




543 




66 5 . 


770 




860 




1000. 






ii 


35o. 


55o 




780 




960. 












2 


625. 


985 




















45 lbs. 


50 lbs. 


60 lbs. 


70 lbs. 


80 lbs. 


90 lbs. 


100 lbs. 


125 lbs. 




I 

04 


.208 


.225 


.26 


•295 


■33 


•364 


.40 


.486 




1 

S2 




843 




914 


I 05 


1. 19 


i-33 


1-47 


I. 6l 


I.97 




1 
TS 


3 


36 


3 


64 


4.2 


4.76 


5-32 


5-8 7 


6-45 


7-8 5 




l 

8 


13 


4 


14 


50 


16.8 


19.O 


21 .2 


23-50 


25.8 


31-4 




J. 

4 


53 


8 


58. 


2 


67. 


76. 


85. 


94. 


103. 


125. 




i 


121 




130 




151- 


171. 


191. 


211. 


231. 


282. 




i 

2 


215 




232. 




268. 


3°4- 


340. 


376. 


412. 


502. 




8 


336 




364 




420. 


476. 


532. 


587. 


645. 


785. 




f 482 




522. 




604. 


685. 


765. 


843- 


925 • 






i 658 




710. 




622. 1 


93°- 


1004. 










1 860 




93°- 






1 











DENSITY OF GASES AND VAPORS 

Air at Same Temperature and Pressure being i.o;~also Weight of a Cubic 
Foot at 62 ° F. Under Atmospheric Pressure 29.92 Inches Mercury 



Density, Air 

at Same 
Temp, and 
Pres. being 

i.o(Regnault) 



Specific Gravity 

or Density, Water 

at 62° being 1.0. 



Weight of a 
Cubic Foot 
in Pounds. 



Cubic Feet 

at 62 ° in 
One Pound. 



Air (atmospheric) 

Hydrogen gas 

Oxygen gas 

Nitrogen gas 

Carbonic acid gas 

Carbonic oxide gas 

Vapor of water 

Vapor of alcohol 

Vapor of sulphuric ether 
Vapor of oil of turpentine 
Vapor of mercury 



1 . 00000 

.06926 

1 .10563 

■97137 

1 .52901 
.9674 
•6235 

1.589 

2 . 586 

4.760 

6.976 



.001221 or fi"9 

. OOOO846 Or U820 

.O0I35O Or 7TT 

.001185 or 

.001870 or 

.00118 or 

.0007613 or 

.00194 or 

.00316 or 

.00581 or 

. 00850 or 



844 
_i_ 
535 

1 
847 

1 

1313 

1 
515 

1 
3 16 
. 1_ 
172 



.O761O 
•00527 
.084I4 

•07383 
. II636 
.O7364 

•04745 
. I 20Q2 
. I9680 
.36224 
•52987 



13 14 
189.7O 

11.88 

13-54 

8-50 

13.60 

21 .07 
8.27 
5-o8 
2.76 
1.88 



APPENDIX N 



349 



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£ ** £ 



xib 



350 SUBWAYS AND TUNNELS OF NEW YORK 



Useful Information — Steam 

A cubic inch of water evaporated under atmospheric pres- 
sure is approximately converted into one cubic foot of steam. 

The horse-power of boilers, as per standard adopted by 
the A. S.M.E., is 30 pounds of water evaporated per hour at a 
pressure of 70 pounds per square inch and from a temperature 
of 100 degrees Fahrenheit. 

Well designed boilers, under successful operation, will evap- 
orate from 7 to 10 pounds of water per pound of first-class coal. 

Each square foot of heating surface is considered sufficient 
to evaporate 2 pounds of water; therefore with an engine using 
30 pounds of water per horse-power per hour, each horse-power 
of the engine requires 15 square feet heating surface in the boiler. 

On 1 square foot of fire grate can be burned on an average 
from 10 to 12 pounds of hard coal, or 18 to 20 pounds of soft 
coal, per hour, with natural draft. 

Two and one-quarter pounds of dry wood is equal to one 
pound of average quality soft coal. 

Steam engines consume fron 12 to 50 pounds of feed water, 
and from i\ to 7 pounds of coal, per hour per indicated horse- 
power. 

Condensing engines require from 20 to 30 times the amount 
of feed water for condensing purposes; approximately for most 
engines, 1 to ih gallons condensing water per minute per indicated 
horse-power. 

Surface condensers for compound steam engines require 
about 2 square feet of cooling surface per horse-power; ordi- 
nary engines will require more surface according to their 
economy in the use of steam. It is absolutely necessary that 
the air pump should be set lower than the condenser for satis- 
factory results. 

The effect of a good air pump and condenser should be to 
get 25 inches of vacuum and to make available about 10 pounds 
more mean effective pressure with the same terminal pressure, 
or to give the same mean effective pressure with a correspond- 



APPENDIX N 351 

ingly less terminal pressure. Approximately, a good condenser 
will save one-fourth of the fuel consumed, or, in other words, 
increase the power of the engine one-fourth, the fuel con- 
sumption remaining the same. 



Useful Information — Water 

One cubic inch weighs .0361 pound. 

One pound equals 27.7 cubic inches. 

One cubic foot equals 62.4245 pounds at 39 degrees Fahren- 
heit; 7.48 U. S. gallons; 6.2321 imperial gallons. 

One U. S. gallon equals 8.331 n pounds; 231 cubic inches; 
.13368 cubic foot. 

One imperial gallon equals 10 pounds at 62 degrees Fahren- 
heit; 277.274 cubic inches; .16046 cubic feet. 

One pound pressure equals 2.31 feet in height. 

One foot in height equals .433 pound pressure. 

Petroleum weighs 6i pounds per U. S. gallon, 42 gallons 
to the barrel. 

To convert imperial gallons into U. S. gallons, multiply 
by the factor 1.2. To convert U. S. gallons into imperial gal- 
lons multiply by the factor .8333. 

A miner's inch is a measure for flow of water, and is the 
quantity of water that will flow in one minute through an open- 
ing 1 inch square in a plank 2 inches thick under a head of 6^ 
inches to the center of the orifice. This is equivalent approx- 
imately to 1.53 cubic feet, or n| gallons per minute. 

To find the diameter of pump plungers to pump a given 
quantity of water at 100 feet piston speed per minute, divide 
the number of gallons by 4, then extract the square root, and the 
result will be the diameter in inches of the plungers. 

To find the number of gallons delivered per minute by a 
single double-acting pump at 100 feet piston speed per minute, 
square the diameter of the plungers, then multiply by 4. 

To find the horse-power necessary to elevate water to a 
given height, multiply the weight of the water elevated per 



352 SUBWAYS AND TUNNELS OF NEW YORK 

minute by the height in feet and divide the product by 33,000 
(an allowance should be made for water friction and a further 
allowance for losses in the steam cylinder, say, from 20 to 30 
per cent). 

The mean pressure of the atmosphere is usually estimated 
at 14.7 pounds per square inch, so that with a perfect vacuum 
it will sustain a column of mercury 29.9 inches, or a column 
of water 33.9 feet high at sea level. 

To determine the proportion between the steam and pump 
cylinder, multiply the given area of the pump cylinder by the 
resistance on the pump in pounds per square inch, and divide 
the product by the available pressure of steam in pounds per 
square inch. The product equals the area of the steam cylinder. 
To this must be added an extra area to overcome the friction, 
which is usually taken at 25 per cent. 

The resistance of friction to the flow of water through pipes 
of uniform diameter is independent of the pressure and increases 
directly as the length and the square of the velocity of the flow, 
and inversely as the diameter of the pipe. With wooden pipes 
the friction is 1.75 times greater than in metallic. Doubling 
the diameter increases the capacity four times. 

To determine the velocity in feet per minute necessary to 
discharge a given volume of water in a given time, multiply the 
number of cubic feet of water by 144 and divide the product 
by the area of the pipe in inches. 

To determine the area of a required pipe, the volume and 
velocity of water being given, multiply the number of cubic 
feet of water by 144 and divide the product by the velocity in 
feet per minute. Cameron Steam Pump Works. 



APPENDIX N 



353 



PRESSURE OF WATER 

The pressure of water in pounds per square inch for every foot in height to 
260 feet; and then, by intervals, to 3000 feet head. By this table, from the 
pounds pressure per square inch, the feet head is readily obtained, and vice versa. 





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134.28 


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94.86 


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136.46 


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26.42 


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138.62 


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26.85 


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49.81 


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140.79 


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27.29 


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96. 16 


330 


142.95 


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4.76 


64 


27.72 


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50.68 


170 


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96.60 


335 


145.12 


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5.20 


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28.15 


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171 


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340 


147.28 


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5-6 3 


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28.58 


119 


51-54 


172 


74 


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225 


97.46 


345 


149-45 


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6.06 


67 


29.02 


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51.98 


173 


74 


94 


226 


97.90 


350 


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6.49 


68 


29-45 


121 


52.41 


174 


75 


37 


227 


98.33 


355 


153-78 


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6-93 


69 


29.88 


122 


52.84 


175 


75 


80 


228 


98.76 


360 


155-94 


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7-36 


70 


30.32 


123 


53-28 


176 


76 


23 


229 


99.20 


365 


158.IO 


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7-79 


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30.75 


124 


53-71 


177 


76 


67 


230 


99 63 


370 


160.27 


19 


8.22 


72 


3i-i8 


125 


54-15 


I 7 8 


77 


10 


231 


100.00 


375 


162.45 


20 


8.66 


73 


3162 


126 


54-58 


179 


77 


53 


232 


100.49 


380 


164.61 


21 


9.09 


74 


32.05 


127 


55-OI 


180 


77 


97 


233 


100.93 


385 


166.78 


22 


9-53 


75 


32.48 


128 


55-44 


181 


78 


40 


, 234 


101 .36 


390 


168.94 


23 


9.96 


76 


32.92 


129 


55-88 


182 


78 


84 


235 


101 . 70 


395 


171 . II 


24 


10.39 


77 


33-35 


130 


56.31 


183 


79 


27 


236 


102 .23 


400 


173-27 


25 


10.82 


78 


33-78 


131 


56.74 


I84 


79 


70 


237 


102 .66 


1 425 


184. 10 


26 


11 .26 


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57-18 


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103 .09 


450 


195.00 


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11 .69 


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34 65 


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57-6i 


186 


80 


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239 


103-53 


475 


205.77 


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12 . 12 


81 


35 08 


134 


58.04 


187 


81 


00 


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103.96 


500 


216.58 


29 


12-55 


82 


35-52 


135 


58.48 


188 


81 


43 


j 241 


104-39 


525 


227.42 


30 


12.99 


83 


35-95 


136 


58.91 


I89 


81 


87 


242 


104.83 


550 


238.25 


3i 


13-42 


84 


36.39 


137 


59-34 


190 


82 


30 


243 


105.26 


575 


249 • 09 


32 


13.86 


85 


36.82 


I38 


59-77 


191 


82 


73 


244 


105.69 


600 


259.90 


33 


14.29 


86 


37-25 


139 


60.21 


192 


83 


17 


245 


106.13 


! 625 


270.73 


34 


14.72 


87 


37-68 


140 


60.64 


193 


83 


60 


246 


106.56 


! 650 


281.56 


35 


15.16 


88 


38.12 


141 


61 .07 


194 


84 


03 


247 


106.99 


675 


292 .40 


36 


15-59 


89 


38.55 


I42 


61.51 


195 


84 


47 


248 


107-43 


700 


303.22 


37 


16.02 


90 


38.98 


143 


61.94 


196 


84 


• 90 


249 


107.86 


725 


31405 


38 


16.45 


9i 


39-42 


144 


62.37 


197 


85 


•33 


250 


108.29 


750 


32488 


39 


16.89 


92 


39-85 


145 


62.81 


198 


85 


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251 


108.73 


775 


335 -72 


40 


17-32 


93 


40.28 


I46 


63.24 


199 


86 


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252 


1 09 . 1 6 


800 


346.54 


41 


17-75 


1 94 


40.72 


147 


63.67 


200 


86 


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253 


109.59 


•825 


357-37 


42 


18.19 


95 


4I-I5 


I48 


64. 10 


201 


87 


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254 


1 1 . 03 


850 


368.20 


43 


18.62 


1 96 


41.58 


149 


64-54 


202 


87 


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1 JO . 46 


1 875 


379 03 


44 


19-05 


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42.01 


150 


64.97 


203 


87 


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256 


110.89 


900 


389.86 


45 


19.49 


98 


42.45 


151 


65.40 


204 


88 


•36 


257 


in. 32 


925 


400. 70 


46 


19.92 


1 " 


42.88 


152 


65.84 


205 


88 


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258 


in .76 


950 


4H-54 


47 


20.35 


100 


43-31 


153 


66. 27 


206 


89 


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259 


112 . 19 


975 


422.35 


48 


20. 79 


101 


43-75 


154 


66.70 


207 


89 


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260 


112 .62 


1000 


433-18 


49 


21 .22 


102 


44.18 


155 


67.14 


208 


90 


. 10 


26l 


113.06 


1500 


649.70 


50 I21.65 


103 


44.61 


156 


67-57 


209 


90 


53 


262 


U3-49 


2000 


866.30 


51 22.09 


104 


45 05 


157 


68.00 


210 


90 


96 


270 


116.96 


3000 


1299.50 


52 22.52 


105 


45-48 


158 


68.43 


211 


9i 


39 


275 


119. 12 






.«n 22.95 


106 


45-91 


159 


68.87 


212 


91 


83 


280 


121 . 29 







354 



SUBWAYS AND TUNNELS OF NEW YORK 



AREAS OF CIRCLES, ADVANCING BY EIGHTHS 

Areas 



6 




1 


1 


3 


1 


5 


3 


7 


S 





8 


4 


8 


2 


8 


4 


8 


o 


.0 


•OI23 


.0491 


.II05 


.1964 


.3068 


.4418 


•60I3 


I 


•7854 


•9940 


1 . 2272 


I.4849 


1. 7671 


2.0739 


2.4053 


2. 7612 


2 


3-14 


3-55 


3-98 


4-43 


4.91 


5-4i 


5-94 


6-49 


3 


7.07 


7.67 


8.30 


8-95 


9.62 


10.32 


11.05 


11.79 


' 4 


12.57 


1336 


14.19 


15-03 


I5-90 


16.80 


17.72 


18.67 


, 5 


19.64 


20.63 


21.65 


22.69 


23.76 


24.85 


25-97 


27.II 


6 


28.27 


29.47 


30.68 


31.92 


33-18 


34-47 


35-79 


37.12 


•' 7 


38.49 


39-87 


41 . 28 


42. 72 


44.18 


45.66 


47-17 


48.71 


l 8 


50.27 


51-85 


53 -46 


55 09 


56.75 


58.43 


60.13 


61.86 


9 


63.62 


65.40 


67. 20 


69.03 


70.88 


72.76 


74.66 


76.59 


IO 


78.54 


80.52 


.82.52 


84-54 


86.59 


88.66 


90. 76 


92.89 


ii 


95-03 


97.21 


99.40 


101 .62 


103.87 


106.14 


108.43 


IIO.75 


12 


113. 10 


115-47 


117.86 


120. 28 


122. 72 


125.19 


127.68 


I3O.I9 


13 


132-73 


i35-3o 


137-89 


140.50 


143-14 


145.80 


148.49 


I5I.20 


14 


153-94 


156.70 


159.48 


162.30 


165.13 


167.99 


170.87 


I73.78 


15 


176.71 


179.67 


182.65 


185.66 


188.69 


I9I-75 


194.83 


197-93 


16 


201 .06 


204. 22 


207.39 


210.60 


213.82 


217.08 


220.35 


223.65 


17 


226.98 


230.33 


233-71 


237.10 


240.53 


243 • 98 


247-45 


250.95 


18 


254-47 


258.02 


261.59 


265.18 


268.80 


272.45 


276.12 


279.81 


19 


283-53 


287.27 


291 .04 


294.83 


298.65 


302.49 


306.35 


310.24 


20 


314.16 


318.10 


3 2 2 . 06 


326.05 


330.06 


334- 10 


338.16 


342.25 


21 


346.36 


350.50 


354-66 


358.84 


363-05 


367.28 


371-54 


375.83 


22 


380.13 


384.46 


388.82 


393 • 20 


397.61 


402.04 


406 . 49 


4IO.97 


23 


415.48 


420.00 


424.56 


429.13 


433 • 74 


438.36 


443 • 01 


447.69 


24 


452.39 


457-n 


461.86 


466 . 64 


471-44 


476.26 


481 .11 


485.98 


25 


490.87 


495-79 


500.74 


505 -7i 


510.71 


5I5-72 


520.77 


525.84 


26 


530.93 


536.05 


54i-i9 


546.35 


551-55 


556.76 


562.00 


567.27 


27 


572.56 


577-87 


583-21 


588.57 


593 96 


599-37 


604.81 


61O.27 


28 


6i5-75 


621 . 26 


626.80 


632.36 


637-94 


643-55 


649. 18 


654 •& 


29 


660.52 


666. 23 


671 .96 


677.71 


683.49 


689.30 


695-I3 


7OO.98 


30 


706.86 


712. 76 


718.69 


724.64 


730.62 


736.62 


742 . 64 


748 • 69 


31 


754-77 


760.87 


766.99 


773-14 


779-31 


785-5I 


791-73 


797.98 


32 


804.25 


810.54 


816.86 


823. 21 


829.58 


•835-97 


842.39 


848.83 


33 


855-30 


861 . 79 


868.31 


874-85 


881.41 


888 . 00 


894.62 


9OI . 26 


34 


907.92 


914.61 


921.32 


928.06 


934.82 


941 .61 


948.42 


955-25 


35 


962. 11 


969 . 00 


975-91 


982.84 


989 . 80 


996.78 


1003 .8 


1010.8 


36 


1017.9 


1025.0 


103 2. 1 


1039.2 


1046.3 


1053 -5 


1060. 7 


1068.0 


37 


1075.2 


1082.5 


1089.8 


1097. 1 


1104.5 


mi. 8 


1119. 2 


1126. 7 


38 


1134.1 


1141 .6 


1 149. 01 


1156.6 


1164. 2 


1171.7 


II79-3. 


1186.9 


39 


1194.6 


1202.3 


1210.0 


1217. 7 


1225.4 


1233.2 


1 241 .0 


1248.8 


40 


1256.6 


1264.5 


1272.4 


1280.3 


1288.2 


1296. 2 


1304.2 


1312. 2 


4i 


1320.3 


1328.3 


1336.4 


1344-5 


1352.7 


1360.8 


1369.0 


1377.2 


42 


1385-4 


1393-7 


1402 .0 


1410.3 


1418.6 


1427.0 


1435-4 


1443-8 


43 


1452.2 


1460.7 


1469. 1 


1477.6 


i486. 2 


1494-7 


1503-3 


1511-9 


44 


1520.5 


1529.2 


1537-9 


1546.6 


1555-3 


1564.0 


1572.8 


1581.6 


45 


1590.4 


1599-3 


1608. 2 


1617.0 


1626.0 


1634.9 


1643.9 


1652.9 


46 


1661 .9 


1670.9 


1680.0 


1689. 1 


1698. 2 


1707.4 


1716.5 


I725-7 


47 


1734-9 


1744.2 


1753-5 


1762 . 7 


1772. 1 


1781.4 


1790.8 


1800. 1 


48 


j. 809. 6 


1819.0 


1828.5 


i837-9 


i847-5 


1857.0 


1866.5 


1876. 1 


49 


1885.7 


1895.4 


1905.0 


I9I4-7 


1924.4 


1934.2 


1943-9 


1953-7 


50 


1963-5 


1973-3 


1983.2 


1993 • 1 


2203.0 


2012.9 


2022.8 


2032.8 



APPENDIX N 



355 



TABLE GIVING RATIOS OF AREAS 

For given diameters of steam and water cylinders. 



1 

Diameter 
of Water 
Cylinders. 


Diameter of Steam Cylinders. 


3 


3i 


4 


5 


6 


7 


8 


9 


1 

10 


12 


14 


5 
8 


23.04 


31.36 


40.97 


64.01 


92.16 


125.45 


163.85 207.37 


256.00 


368.64501.76 


3 

4 


16.00 


21.77 


28.45 


44.45 


64.00 


87.12 


113.78 144.00 


177.77 


256.00 348.44 


7 
8 


11.75 


16.00 


20.90 


32.66 


47.02 


64.01 


83.60 


105.80 


130.61 


188.09 


256.00 


1 


9.00 


12.25 


16.00 


25.00 


36.00 


49.01 


64.00 


81.00 


100.00 


144.00 


196.00 


1* 


7.11 


9.68 


12.65 


19.76 


28.44 


38.73 


50.57 


64.00 


79.01 


113.77 


154.87 


11 


5.76 


7.84 


10.24 


16.00 


23.04 


31.37 


40.97 


51.85 


64.00 


92.18 


125.46 


If 


4.76 


6.48 


8.46 


13.23 


19.04 


25.92 


33.85 


42.84 


52.89 


76.16 


103.66 


1* 


4.00 


5.44 


7.11 


11.12 


16.00 


21.78 


28.45 


36.00 


44.45 


64.00 


87.12 


If 


3.41 


4.64 


6.06 


9.47 


13.63 


18.56 


24.24 


30.68 


37.87 


54.53 


74.22 


If 


2.94 


4.00 


5.23 


8.17 


11.75 


16.00 


20.90 


26.45 


32.66 


47.03 


64.00 


H 


2.56 


3.48 


4.55 


7.11 


10.24 


13.94 


18.21 


23.04 


28.44 


40.96 


55.75 


2 


2.25 


3.06 


4.00 


6.25 


9.00 


12.26 


16.00 


20.26 


25.00 


36.00 


48.09 


21 


1.78 


2.42 


3.16 


4.93 


7.10 


9.67 


12.63 


15.98 


19.73 


28.42 


38.68 


2* 


1.44 


1.96 


2.56 


4.00 


5.76 


7.84 


10.24 


12.96 


16.00 


23.04 


31.35 


2f 


1.19 


1.62 


2.12 


3.31 


4.76 


6.48 


8.46 


10.72 


13.22 


19.04 


25.92 


3 


1.00 


1.36 


1.78 


2.78 


4.00 


5.43 


7.11 


9.00 


11.11 


16.00 


21.77 


31 


.85 


1.16 


1.51 


2.37 


3.40 


4.64 


6.06 


7.67 


9.46 


13.63 


18.55 


3* 


.73 


1.00 


1.31 


2.04 


2.94 


4.00 


5.23 


6.61 


8.17 


11.76 


16.00 


31 


.64 


.87 


1.14 


1.78 


2.56 


3.48 


4.55 


5.76 


7.11 


10.24 


13.93 


4 


.56 


.77 


1.00 


1.56 


2.25 


3.06 


4.00 


5.06 


6.25 


9.00 


12.25 


41 


.50 


.68 


.89 


1.38 


1.99 


2.71 


3.54 


4.49 


5.53 


7.97 


10.85 


4^ 


.44 


.61 


.79 


1.23 


1.78 


2.42 


3.16 


4.00 


4.94 


7.11 


9.68 


4f 


.40 


.54 


.71 


1.11 


1.60 


2.17 


2.84 


3.59 


4.43 


6.38 


8.68 


5 


.36 


.49 


.64 


1.00 


1.44 


1.96 


2.56 


3.24 


4.00 


5.76 


7.84 


5* 


.30 


.40 


.53 


1.00 


1.19 


1.62 


2.12 


2.68 


3.30 


4.76 


6.48 


6 


.25 


.34 


.45 


.83 


1.00 


1.36 


1.78 


2.25 


2.78 


4.00 


5.45 


6§ 




.29 


.38 


.69 


.85 


1.16 


1.51 


1.92 


2.37 


3.40 


4.64 


7 




.25 


.33 


.59 


.73 


1.00 


1.31 


1.65 


2.04 


2.94 


4.00 


7| 






.28 
.25 


.51 
.44 

.39 
.35 
.31 
.28 
.25 


.64 
.56 

.50 
.44 
.40 
.36 
.33 
.30 

.25 


.87 
.77 

.68 
.60 
.54 
.49 
.44 
.40 

.34 
.29 
.25 


1.14 
1.00 

.89 
.79 
.71 
.64 
.58 
.53 

.44 
.38 
.33 
.28 
.25 


1.44 
1.27 

1.12 
1.00 
.90 
.81 
.73 
.67 

.56 
.48 
.41 
.36 
.32 
.28 
.25 


1.78 
1.56 

1.38 
1.23 
1.11 
1.00 
.91 
.83 

.69 
.59 
.51 
.44 
.39 
.35 
.31 


2.56 

2.25 

1.99 
1.78 
1.60 
1.44 
1.31 
1.19 

1.00 
.85 
.74 
.64 
.56 
.50 
.45 


3.48 


8 






3.06 


8§ 






2.71 


9 








2.42 


9| 








2.17 


10 








1.96 


10| 








1.77 


11 








1.62 


12 










1.36 


13 










1.16 


14 












1.00 


15 












.87 


16 














.76 


17 














.68 


18 
















.60 






I 















356 



SUBWAYS AND TUNNELS OF NEW YORK 



TABLE GIVING RATIOS OF AREAS— {Continued) 



a.ter 
iter 
lers. 








Diameter of Steam Cylin 


ders. 






























03 . — i 

Qo£ 


16 


18 


20 


22 


24 


26 


28 


30 


32 


34 


36 


5 
8 
3 

4 


455.09 






















7 
8 


334.37 
























256.00 324.00 400.00 


















1 1 
A 8 


202.27 


256.00 


316.05 


















1 1 

■•■a 


163.86 


207.38 


256.00 


309.81 
















1 3 

- 1 8 


135.39 


171.47 


211.69 


256.00 
















1 1 
x 2 


113.78 


144.00 


177.77 


215.11 


256.00 














-1-8 


96.94 


122.72 


151.54 


183.37 


218.22 














1 3 
A 1 


83.60 


105.79 


130.61 


158.05 


188.10 


220.71 












1 7 

- 1 8 


72.82 


92.16 


113.78 


137.67 


163.85 


192.29 












2 


64.00 


81.00 


100.00 


121.00 


144.00 


169.00 


196.00 225.00 


256.00 






2| 


50.56 


64.00 


79.01 


95 . 60 


113.78 


131.56 


154.87177.77 


202.27 






2i 


40.96 


51.84 


64.00 


77.44 


92.16 


108.16 


125.44 144.00 


163.84 


184.97 




21 


33.85 


42.84 


52.89 


64.00 


76.17 


89.39 


103.66119.01 


135.4l|l52.86 




3 


28.44 


36.00 


44.44 


53.77 


64.00 


75.11 


87.11 100.00 


113.77 128.44 


144.00 


3i 


24.23 


30.67 


37.87 


45.83 


54.54 


64.00 


74.24 


85.22 


96.96 


109.46 


122.72 


31 


20.90 


26.44 


32.65 


39.42 


47.02 


55.18 


64.00 


73.47 


83.59 


94.36 


105.79 


31 


18.20 


23.04 


28.44 


34.42 


40.96 


48.07 


55.75 


64.00 


72.82 


82.21 


92.16 


4 


16.00 


20.25 


25.00 


30.25 


36.00 


42.25 


49.00 


56.25 


64.00 


72.25 


81. CO 


4i 


14.17 


17.93 


22.14 


26.79 


31.89 


37.43 


43.41 


46.51 


56.69 


64.00 


71.76 


4* 


12.64 


16.00 


19.75 


23.90 


28.44 


33.33 


38.71 


44.44 


50.56 


57.08 


64. CO 


4i 


11.34 


14.36 


17.73 


21.45 


25.53 


29.96 


34.75 


39.89 


45.38 


51.24 


57.44 


5 


10.24 


12.96 


16.00 


19.20 


23.04 


27.04 


31.36 


36.00 


40.96 


46.24 


51,84 


51 


8.46 


10.71 


13.22 


16.00 


19.04 


22.33 


25.91 


29.75 


33.85 


38.21 


42.84 


6 


7.11 


9.00 


11.11 


13.44 


16.00 


18.77 


21.77 


25.00 


28.44 


32.11 


36.00 


61 


6.06 


7.66 


9.46 


11.45 


13.63 


16.00 


18.56 


21.30 


24.23 


27.36 


30.67 


7 


5.22 


6.61 


8.16 


9.87 


11.75 


13.79 


16.00 


18.37 


20.90 


23.59 


26.44 


7i 

' 2 


4.55 


5.76 


7.11 


8.60 


10.24 


12.00 


13.93 


16.00 


18.20 


20.55 


23.04 


8 


4.00 


5.06 


6.25 


7.25 


9.00 


10.56 


12.25 


14.06 


16.00 


18.06 


20.25 


81 


3.54 


4.48 


5.53 


6.69 


7.97 


9.35 


10.85 


12.45 


14.17 


16.00 


17.92 


9 


3.15 


4.00 


4.93 


5.85 


7.11 


8.34 


9.67 


11.11 


12.64 


14.27 


16.00 


91 


2.83 


3.59 


4.43 


5.36 


6.38 


7.49 


8.68 


9.97 


11.34 


12.88 


14.36 


10 


2.56 


3.24 


4.00 


4.84 


5.76 


6.76 


7.84 


9.00 


10.24 


11.56 


12.96 


10J 


2.32 


2.94 


3.63 


4.39 


5.22 


6.13 


7.10 


8.16 


9.29 


10.48 


11.75 


11 


2.11 


2.67 


3.30 


4.00 


4.76 


5.58 


6.47 


7.43 


8.46 


9.55 


10.71 


12 


1.77 


2.25 


2.77 


3.36 


4.00 


4.67 


5.44 


6.25 


7.11 


8.02 


9.00 


13 


1.51 


1.91 


2.37 


2.86 


3.40 


4.00 


4.63 


5.32 


6.06 


6.83 


7.66 


14 


1.30 


1.65 


2.04 


2.46 


2.93 


3.44 


4.00 


4.59 


5.22 


5.89 


6.61 


15 


1.13 


1.44 


1.77 


2.13 


2.56 


3.00 


3.48 


4.00 


4.55 


5.13 


5.76 


16 


1.00 


1.26 


1.56 


1.89 


2.25 


2.64 


3.0G 


3.51 


4.00 


4.51 


5.06 


17 


.88 


1.12 


1.38 


1.67 


1.99 


2.34 


2.71 


3.11 


3.54 


4.00 


4.48 


18 


.79 


1.00 


1.23 


1.49 


1.77 


2.08 


2.41 


2.77 


3.15 


3.56 


4.00 



APPENDIX N 



357 



W N P~0 OlHIflH 

N rtO iflO ^t^NfCiflfOMOO "JO "5 hoon r~00 r~ N O O 

O <taOH iflO t^O OMHOrOMMfOOONiO^moOO 1COO N <?t PO WNN l^O 00 « M 

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w 


U 





„-_^^- .-|-*»-!mwHi r^Hi^lw"!* H-*»«1nwI^i ^t-*t--l«rtW^ nw fh|m 

N N N N POPOPOPO't't't'tlOtOlO too O O O r- t^oo o O O i-i N P0 't too 00 O N Tt 

MMMMMHHWHNNN 



358 



SUBWAYS AND TUNNELS OF NEW YORK 



o 



J3 

M 

a 

G 

+j 
O 
O 
Ph 

M 

s- 

o 

Ph 


Gallons of 

231 Cubic 

Inches. 


• 
rOHMui 00 >oo oowoooo i'ttw nhoo poo 00000 nooooo r~ ^ On cm po po 

MflOH O\00 I>0 lOiOi/JLOiOt^-ONCOt^CM >^h OnOO 00 ftO N lOOi't OnO rOH O 


rj- 100 r- t-00 OvO n CM po v> t^ On m *o Oh rj- j> On CM 1000 CM 1000 m toco CM O O "*■ 

HHHMHHHNPlNOtNNNfO^nOt't't^l'll'l IOO 00>h t^OO 00 On O. 


Cubic Ft. 
Also Area 
in Sq. Ft. 


Oi^tN NiflH O h«n N Oi c^O 'Ot^OiHi'lO i«h Oi r^vo O t>00 h 10 On wi m 00 O 
O 1^00 OlO N ^O M H <tooo i-> t-00 O ^too rt-Ooooo f~ O CM O MOO lO^T}- Tf O 
OiO h N ^ 10O r-00 O m "^O O N 10 Oi (M U5 Oi POO O ^00 N >h>0 O 10O lOO 10 


HNNWMNNMMflrlCJfltTT^t^lfllfl LOO vO l~- t> t^OO OOOOnOOwmCMCM 

IH M IH M W IH 


Diameter 

in Decimals 

of a Foot. 


PO >o r^oo OMOU) r~oo O po r- O PO i> O rot^O PO r- O PO r~ O CO t^ O PO r~ O POt^O 

KNiOOino.o^HvicoovOi'J^HOoovoi'ifOHOooioi'ifOHOoooionHO 
iflO r- r- i>oo M QOO Ohm m^-io wo r~oo aOOH n to^") loo c-oo On O 


HHMWHHiHiHiHiHCMCMCMCMCMCMCMCMCMCMCMCMPOPOPOPOPOPOPOP0P0P0POP0' , =t 


(Urd 

Eg 

nJi— I 


rH|N rH|N W|N rt|f* HN 

On O ih M ro •r)-L0Or~00 0N0iHCMP0 ,H fL0OJ'~00 0N0iHCMP0' rf rL0Oi>00 
w cm cm cm cm NNNNr)c,^flcootonr<)roPOt , >'*'t , t' , t't"*"t , t't 




+-> 

bo 
C 
o 
-1 
G 

O 

o 

Ph 

H 

o 

ft, 


Gallons of 

231 Cubic 

Inches. 


OOiUHOO m t^-00 ioujh cm On O O 00 ION TfO tOiflVl LOO t^00 O M 

lo On -H/ O lo m f~"^-(N O OnOO t^-00 00 On m POO On PO t— t- On PO On l>00 O ■ h t >h On On CM O 

00 Onh cm rtvO t«0\H po ^O 00 O cm ^rt^OiH PO O 00 PO 00 ^On")ho0 ^ m i^-^-m On 


m m cm cnj CM CM CM cm cOPOPOPOPOTt-''3'' , 3 -,H r' ; cl"LOLOLO LOO O t- l>00 OnOnOmhcmpOpO 

M M M M H M 


Cubic Ft. 
Also Area 
in Sq. Ft. 


lo po r^oo O w cm hnOoo i>- cm lo *t O po po O po po O "3-cmoo O 

00 i>0 Ot~0>-i' rf rr^MOCMooioro>HOOOM(-oir)CMi-iTj-ONt^i>ONO loo O r»- r~ 

"^rO 00 O CM "+ r- On m "3"0 O* i-i Tj- t^ O POO O. CM LO00 ID CM OO Tf CM M OnOO t— t^-O O 

cm cm cm coP0P0P0P0' H r'^t T ^"" ; d - io lo'loO O O O r- r- t^oo O1O1O h in rof)^ loo t~oo 


HHMHMMMMMM 


Diameter 
in Decimals 
of a Foot. 


iOPOCMOoOI>i«rOCMOoOI>i^rOMOoOI>uoroCM 

cm ro -h/ 10 ino t^oo (joOHNot") 100 t^oo ao « toifl t^oo cm ro 10 r^oo o cm 
OX O N ■HrO 00 O cm lor^ONW comt-Ow rijiot^O -htoo oiOOioOcOt^Mioo^t 
inu^OOOOO r~t^t^t^r~oooooooooo OnoOOnO O O m m cm cm cm roro ,ri r' ri rio»o 


MHMMMHHMMMMMMHM 


CL)H-i 

eg 

oil— i 


«]■* H'*h|««1'* rth«H[Nnl-* H'JHlNnl-* ih!-«h|««H< mKhImpH'* h|n fh]ci h|n ~\c* h]m rn|« h« 
t^ 00 On O m CMrOTtioOl>oo 

M M WMMMMHM 




^5 
+i 
bfl 

a 

a> 
h-J 

a 

-tj 
o 
o 
Pn 

M 

Ih 
O 
Ph 


Gallons of 

231 Cubic 

Inches. 


vo O t^OO CM On On ro O Oi M O00 OOOOOnCMOOiocmOOOOOOOOn COO 
M-^-tot^OCMLoO <~0O w 10 C CO w "^- POO VO00 r~M OPOMOO O O U'5T)-ONON' H r' H r 

OOOO1-1WMIHCMMPOPO TnO CNCMOOIOOOPOO, I>lOP0CMCMCMCMPO ■sfo O CM 

oooooooooooooooHwcMCMPOPO ,rf r -H rvooi>oooNOiHCMPo^j - voi> 


W M M M W M H 


Cubic Ft. 
Also Area 
in Sq. Ft. 


PO VOOO O 'd-^wO >iO CMOO LTjiOPO r-00 O ih CM MO00 t^rOifl^H ^(^q f^j (^5 ,_, ^ 
OOOiHtHiHCMCMPOco' H r" H riA)oocMOiHC-'HriHOr-ooi>ocOPOOOiooopOO 
OOOOOOOOOOOOOO>HiHCMMP0"^" ,t 1" 10O t^00 O. ih M PO 100 00 O ih PO 
OOOOOOOOOOOOOOOOOOOOOOOOOCMMMMMMMPqCM 


Diameter 

in Decimals 

of a Foot. 


00 O POmt^Ow roiflf-OH POCM O00 t-iOPOCM Ooo t^iOPOCM OOO t^lOPON 000 t^ 
OO mO hO cm r^CM t^CMOO P0^r<O ionO t^oo OO O h m n^-ifl too r^oo On O O ih 
cm pj po PO ^" ^" »o 100 O t> t~-oo O m ^O 00 O cm iflNttH POior-ONiH POior^O o) "3- 

ooooooooooooOHHHHHciNNNNtcnfOdo^'j'ti'ioi'jio 






ir! °5 

al 

nil— 1 

S.S 


r<*J»M|«o i J«H|ei J«io|ooH|'OBi*»NOi.| m iato rtlfHlNnl-* r<HMNn|-» •HMrflNnl-* HNriMnM H«H|MaI'« h|-»h|n 
">«Tr< s >t'- , H H HHlH M cm PO -t lO O 



APPENDIX N 



359 













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t^ CJ\ (N r~- co 

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M IH M CM CM 



0\ io « cm coO moo r^oo O 

u-jr^o^M co vo 00 O fO^C O 

m m i-: m cm o cm co 



Tf vo 



IT) 1^ N N ONf^O CO O O* O 

N Oi h "3- vO O PTO O co 00 
mhmmc-icmcococo 



00 

CO 


io 

VO 


vo oo cm 
r~» o\ cm 

M 


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VO 00 
H M 


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CM 
CM 


QO 
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O vo 

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00 CM 

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t^ 00 
O vO 


to 
co 


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^ lOOO 
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r^ co ^J- 

O CO N 



O CM 



ON N O f) N NMD W 
<N On VO CO H On 00 00 
co co "^ vo -O vO t~» O0 



t^ 00 ih vooo t^-CM coO 't N OO OO O 00 OO 

co-htO r^O H; a "t o ^O coOoo n ao 

M M ih CM co co "3- vo vo no r-~ 00 



rOiflO>iO^-fOMO 

C) "t lO N 6 MOO co 

M n CM 



O O 00 co vO no -HfOO o 
Ox^--H r co<N o) co'^t-r^- 
coco-st-vovo r^ 00 OvO 



vo vo r-~ ov oo 
t-» On h \0 cm 

H H CM 



O OvOvt^vooO On^ 
O *>■ vO vO r^-00 m vo 
coco^vovo N a O 



00 vo vo 00 ^- 
co vo t^ Q\ cn 



co O 

VO CM 
M CM 



O W O O M CM 

O On On O ■<*■ oo 
co co -*• vo r*» oo 



■H/ CM VO CM 
CO vo t^ O 



h Ov 00 O 00 rj- O cooo 
■Hrvo O O Ovo vocoO 

H M CN CO-HrVOVOOO O 



1"-. OO vo 00 


N N fO 


O CM 00 OO CM 


CO ■>*■ J>- O 


^f Ov ^1- 


O fOOO O N 


IH 


M IH CM 


CO "3- vo t^ Ov 



N O O O O OvvoO 

H vO co O 00 no t^» CM 
HMCMCOCO-rt-vOOV 



^t-COHO^-VOCMM 

covocm o ■+ a h oo 

H M <N COCO'HrVOOO 



CM Tf On O 00 covoco 

OcoOOOcor^co 

H m cn co-nJ-voOOO 



1^- CM O M OO 00 

-t a o co oo vo 

M m ro ^ lO N 



O O Ov vo O 
co O vo r~^ cm 

CM co -H/ vO On 



t. e u 
o)CJ< 

§co| 



Hn 
CO 



•H/ vo vo r^ oo Ov O 



cm ^ vo 00 O 

M M M M CM 



CM rJ-vO 00 
CM CM CM CM 



O CM ^ NO 
CO CO CO CO 



360 



SUBWAYS AND TUNNELS OF NEW YORK 



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in 
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3 


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14 


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Contents 

in 

Gallons. 

per Foot. 


\0 ^O N 

O <n to 

o o o 
o o o 


cn o oo oo oo cn 
O co O CO m co 
H CN <3- VO O VO 
O O O O O m 


O CO 00 00 CO 
to r>. O vn vo 
to vo On to CN 
CN CO "tvO 00 


O On On hi O m 
CN vo On hi O yO 
O "*■ On vO CO O 


co t^- 

O 00 












M H H CN CO ^ 


TT to 


Number 
of 

Threads 
per Inch, 
of Screw. 


f» 00 00 

CN HI HI 


.H|CN >-l|M iH|ff» 

rf "cr m h m 

M H M M H 


H 
H 


00 00 00 


00 00 


00 00 00 00 00 00 


20 00 


Nominal 

Weight 

per Foot. 

Pounds. 


co cn hi to vo CO Tf n 

■^-(NVO ^T CN l>- to On VO 

CM <t 1O00 H VO CN NO VO 


to N IOCO TT t^ OOJ^M 
N rt" lO M TTVOvO m tJ-1>."vJ- 
MO O NtO>ON^toOvO 


00 
O On 


o 


M M CN CN 


CO 


lO N O 


O CN. 

M HI 


rj- 00 to 00 "tO 
HI M CN CN CO TT 


to 00 


Length of 
Pipe Con- 
taining I 

Cubic 

Foot. 

Feet. 


O O io 


to to VO 
•^ O O CN vO <0 


H O vO 

Hi ^ tO 


HI CO 

co O 


O 00 CN 00 vo O 
CN On f^ 00 CN 00 


O t^ 

to CN 


O to M 
O oo to 

to <o r^ 

CN H 


cn O vO vo O 
i>. r^ vo On t~» 

^- CN H 


CN 


O O Tf 

CO M M 


hi On 

HI 


r^ ^- CO CN CN HI 


HI HI 


External 

Area. 
Inches. 


O ONCO 
CN CN tO 

h cn co 


t)-nO N -t ifl 
to vo to vo CO 
to 00 CO M 00 


o 

CO 


M M VO 

On CN vO 
"<*■ vO to 


■>cj- to 
O co 

O vo 


O H co vO to CN 
On r^ vo CN HI vo 
cn *st- vo "3- r^ r>- 


co J^- 
•>*■ vo 




H CN CN 


TT VO O CN 
H 


to O 

HI HI 


TT ^ VO 00 CO O 

CN CO ^- to !>• O 


00 t»- 

O CN 

M HI 


Internal 

Area. 

Inches. 


<N H VO 
to O O 

O M l-l 


CO fO N 
■^- CO CN VO 00 
O CO vO On co 

co to oo ^r O 


lO tOCO N 
to 00 00 00 
CO N fOCO 


O On 
co co 
t^- On 


On f» On co 00 
On OO CO <0 to CO 
On 00 N O vO OO 


CO 

o o 




H CN 


<o 


^ N O 


CN tO 

HI HI 


On 00 00 CO 00 

H CN CO tO VO 1>- 


to CO 

On m 

HI 


Length of 
Pipe per 
Square 
Foot of 
Outside 
Surface. 
Feet. 


to !>■ 

*4- r- to 

Tt O VO 


cn r^ co w 
O co O O m 
to vo O fO O 


H 

i— l 

vO 


O0 H l00100»N10<t') ,u ! 

cn Oto-^-vo <n r^-O ^ On to 
COO On00 !>• vO io io ri- to to 


CN O 

to CO 


O t^ lO 


•^ CO CN CN CN 


H 


H H 








Length 

of Pipe per 

Square 

Foot of 

Inside 

Surface. 

Feet. 


vo O t~ 

H lO VO 


tO O 00 H CO 
CO CO t~» vO t^- ^ - 
H VO VO t^- CO 00 


N ION 
-* ^ t- 
tO CN O 


O 00 

O 00 


t^» Tj- 00 tO HI 

lO to <t J^ N 00 
t^ vo to -sT -^ ^o 


co co 


•^•O r^.vo tJ- to cn cn 

H M 


H 


H H H 








External 
Circum- 
ference. 
Inches. 


r^ Ov cn 

CN VO H 


CN On ^T to On 
to On CO M vO 
vO CN H CN O 


M 
VO 


CN VO vO 

co O VO 
O O to 


r->- oo 
CO O 

M 1>- 


to CO Tj- vO co CN 
J>- M to On co t~- 

•^- oo o O -<cr t~- 


H to 

On O 


H HI CN 


CN co -rt" to to 


r^ 


On O <N 

M H 


Tf tO 

H HI 


X^O to N O tovo 

HI <N CN CM CO CO CO '-J - 


Internal 
Circum- 
ference. 
Inches. 


00 TT CN 

^- n- lO 

OO HI tO 


r^ On CN to M 
to OO O co vO 
On to CN co O 


<* 

O 
<* 


^ vo vo 

to co •^r 

t^. VO H 


00 CO 

■sr to 

VO HI 


O ^r co vo r>. io 
Tf to vo r^ t>» t— 

oo O O O CN vt- 


to O 
to t^ 


H M 


H CN CO "si" to VO 


J>. O M 
H 


CN Tj" 

M M 


to On cn to 00 hi 

HI M CN CN CN CO 


CO CO 


Actual 

Outside 

Diameter. 

Inches. 


to to 
O -*r *- 

Tj- IOVO 


to 

tJ- to M vO 
00 O co vo On 


to to 

CO 00 to O 


to O 


CO to to to 00 

VO CN CN CN 00 to 
to vo vO vO vO t-» 


to to 


1 


HI HI HI HI 


CN 


N tO t 


Tj- to 


to vo t^ 00 O O 

HI 


HI CN 

HI HI 


Actual 

Inside 

Diameter. 

Inches. 


O tt •* to "d- oo O m 
r^ vo Ovcn cn -rroo m 

CN co^-vOOO O CO vO 


NO 

o 


CO NCO 

vo VO Hi 

^ O to 


VO 00 
CN O 

O to 


tO to CO CN HI On 
•^- VO CN 00 O M 

o o o o o o 


O 




M Hi HI 


CN 


CN CO CO 


Tf Tj- 


to vo t^ r^ o O 

HI 


HI CN 

HI HI 


Nominal 

Inside 
Diameter. 


iH|00 rtl-* m|oo 


He* mMi hHih|h 

HI HI M 


CN 


i-llN Hco 
CN CO CO 


1H|N 


to vo t^- 00 On O 

H 


HI CN 

HI HI 



APPENDIX X 



361 






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M M CM CM rO tO 't ^f >0 N O CM Ifl N O IOO IOO IOO 


MMMH-lCMCMCOCO''3"'<3" 1 -0 


T*\ ^ *3 






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y s 3 


























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cm 










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u 5 3 
























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HWOO*OVOOOO<NO 






















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A 
c 


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*** 


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C Cm 






































A 


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«5 O *«• "*" O 




































u 


+3 03 C 






































c 


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■"■' 


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m cm 10 r-~ 




































»|-* 






































O 


£ G o5 

PMC 


z> 










































c 


.2 g 3 

C 2 


<t 

M O 










































•H(M 












































allons 
Dis- 
arged 
per 
inute. 


ioOioO^oOloO^oO^OloO^OO OOOOO 


M M CN cm to f^ "t ^ ^ t^ O CM Ifl N O 10O w> O 10O 


MMMMCMCMCOCOTf^lO 


O 


•g s 















































362 



SUBWAYS AND TUNNELS OF NEW YORK 



< 
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charged 

per 
Minute. 


o o o o o 

m O to O f~ 

<N io !>• O cm 

M M 




o 

H 


o 

M 


O 
O 
O 

CM 


o 

LO 
CM 

CM 


O 

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O 
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o 
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CM 
CM 

o • 


iooO vo co in h 
co ^- no oo O co 

O O O O M M 


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cm 


n C " 
'+-> to C 

O K H 








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o • 

CM 

o • 




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NO 

o : 


cm no no in co o 

O TT On in CM On 

M H M CM CO CO 


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o 

.2 

o 
cm 


■p to C 
•C ° o 








CM 

M 

o : 






CM 

o : 




M 
On ' 

o ; 


oo 
m ' 

H 


"vT 00 CN1 CM 
■^ ^ t^ M 
CM CO ^ NO 






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M H CM CM CO ^t lO \ 










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M 


Sew 

'-!-> to C 

o to 3 

•C o o 




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00 NO no J^ On co ' 
m cm co Tr in t^ \ 












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Sew 

■+j to C 
u to 3 

■C°o 




• M 

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NO M On m 
CO lO NO On 
















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to be <-• 3 

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■S s 




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APPENDIX N 



363 



POUNDS PRESSURE LOST BY FRICTION 

In each ioo feet of 25-inch fire hose, for given discharges of water per minute. 



in 

<4-l <U 

O Xi 
u 


Pressure at Hose Nozzle. 


Q 
2 


Head in pounds per sq in. 
Head in feet 


20 
46.2 


30 
69.3 


40 
92.4 


50 60 
115. 5 138.6 


70 

161 . 7 


80 
184.8 


90 100 
207.9 231.0 


1 

if 
ii 
if 


< Rubber hose, pounds. . . 
Leather hose, pounds . . 

1 Gallons discharged 

< Rubber hose, pounds. . . 
(_ Leather hose, pounds. . . 

j Gallons discharged 

{ Rubber hose, pounds . . . 
1 Leather hose, pounds. . . 

< Rubber hose, pounds. . . 
[ Leather hose, pounds . . 


no 
4-35 
6.33 

139 

6.79 

9-05 

171 
10.28 
12.84 

207 
15.0 
18.81 


134 
6.40 

8.53 

170 
10. 16 

12.71 

210 
15.64 
19.0 

253 
22 .96 
26.39 


155 

8.40 
10.83 

196 
1360 
16.38 

242 
20.85 

24.07 

293 
29.40 
35-01 


173 
10.20 
13- 10 

219 

17.05 

20. II 

271 
25.46 
30. II 

327 
40.50 
43.38 


189 

12.80 

15.34 

240 
20.59 

23.88 

297 
29.50 

35-94 

358 
48.20 
52.0 


205 

14.80 

17.79 

259 
24.0 
27.61 

320 
39-0 

41-57 

387 
55-70 
60.40 


219 
17 .0 
20. 11 

277 
27 .0 
31.41 

342 
43.8i 
47.36 

413 
64.70 
68.59 


232 
19. 20 
22.40 

294 
30.0 
35.24 

363 
49.42 
53.25 

439 
72.0 
76.73 


245 

20.50 

24.83 

310 
330 
39.07 

383 
55-0 
59-20 

462 
7926 
84.87 



HORIZONTAL AND VERTICAL DISTANCES REACHED BY JETS 



£ 1 
Q ° 



Pressure at Nozzle. 



ii 



if 



Head in pounds per sq. in. 



Head in feet 



[ Gallons discharged. . . . 

\ Horiz. distance of jet 

Vertical distance of jet 



Gallons discharged. 



I 

r 

■i Horiz. distance of jet 
[ Vertical distance of jet 

Gallons discharged. . . . 
•i Horiz. distance of jet . 
[ Vertical distance of jet 



Gallons discharged. . . . 
Horiz. distance of jet . 
Vertical distance of jet 



30 



46.2 69.3 



no 

70 
43 

131 
71 

43 

171 
73 
43 

207 

75 
44 



134 
90 
62 

170 
93 
63 

210 
96 
63 

253 

100 

65 



40 



50 



60 



70 



92.4 115. 5 138.6 161. 7 



155 

109 

79 

196 
113 

81 



173 
126 

94 

219 

132 

97 



242 271 
118 ' 138 
82 99 



293 

124 
85 



327 
146 
102 



189 
142 

108 

240 
148 
112 

297 
156 

115 

358 
166 
Il8 



80 



184.8 



205 219 

156 168 

121 131 

259 277 

163 175 

125 137 



320 
172 
129 



342 
186 
142 



387 413 
184 200 
133 146 



90 



IOO 



207 .9 23I.O 



232 
178 
140 

294 
186 
148 

363 
198 
154 

439 

213 
158 



245 
186 
148 

310 
193 

157 

383 
207 
164 

462 
224 
169 



364 



SUBWAYS AND TUNNELS OF NEW YORK 



FRENCH OR METRIC MEASURES 

The metric unit of length is the meter = 39.37 inches. 
The metric unit of weight is the gram = 15.432 grains. 

The following prefixes are used for sub-divisions and multiples : Milli = y-^oo", 
Centi = y-Q-^, Deci = y 1 o> Deca = io, Hecto = ioo, Kilo =1000, Myria = 10,000. 

FRENCH AND BRITISH (and American) EQUIVALENT MEASURES 

Measures of Length 

French. British and U. S. 

i meter =39-37 inches, or 3.28083 feet, 1.09361 yards. 

.3048 meter = 1 foot. 
1 centimeter =-3937 inch. 
2.54 centimeters = 1 inch. 

1 millimeter = .03937 inch, or -g 1 ^- inch nearly. 
25.4 millimeters =1 inch. 
1 kilometer =1093.61 yards, or .62137 mile. 

Measures of Capacity 

j 61.023 cubic inches. 
.03531 cubic foot. 



1 liter ( = 1 cubic decimeter) 



28.317 liters 
4.543 liters 
3.785 liters 



French. 
i gram 
.0648 gram 
28.35 gram 
1 kilogram 
.4536 kilogram 

1 tonne or metric ton 1 



1000 kilograms 

1. 01 6 metric tons 
1 01 6 kilograms 



.2642 gallon (American). 
[ 2.202 pounds of water at 62 ° F. 
= 1 cubic foot. 
= 1 gallon (British). 
= 1 gallon (American). 

Measures of Weight 

British and U. S. 

= 15-432 grains. 

= 1 grain. 

= 1 ounce avoirdupois. 

= 2.2046 pounds. 

= 1 pound. 

.9842 ton of 2240 pounds. 

19.68 rwts. 
I 2204.6 pounds. 

= 1 ton of 2240 pounds. 



J 
1 



} 



COAL CONSUMPTION 



The average coal consumption may be taken as follows, an evaporation of 
8 pounds of water to 1 pound of coal being assumed: 

For non-condensing engines 3 to 5^ per I.H.P. per Hour. 

For condensing engines 2 to 4 

For compound non-condensing engines 2.5 to 3 

For compound condensing engines 1.6 to 2.75 

For triple condensing engines 1.25 to 1.75 

For quadruple condensing engines 1 to 1.5 



APPENDIX N 



365 



HEAT OF COMBUSTION OF FUELS 

Air Required per Total Heat of 

Pound of Fuel in Combustion of 

Cubic Feet at i Pound of 

62 F. Fuel in B.T.U. 

Coal 140 14 . 700 

Coke 142 13 . 548 

Lignite 116 13 . 108 

Asphalt 156 17. 040 

Wood, dry 80 ic . 974 

Wood, 20 per cent moisture 60 7 . 951 

Wood charcoal, dry 125 13 .006 

Peat, dry 99 12 . 279 

Peat, 30 per cent moisture 69 8 . 260 

Straw 56 8 . 144 

Petroleum 188 20.411 

Petroleum oils 235 27.531 

Coal gas, per cubic foot at 62 ° F . 630 

In practice it is found that from 18 to 24 pounds of air is required for the 
combustion of each pound of coal, according to whether forced or natural draft 
is used. 



FEED-WATER CONSUMPTION 

Average weight of feed- water used per I.H.P. per hour, in pounds. 

Water 

Type of Engine. Boiler Pressure. Consumption. 

Slide valve, throttling N.C. 80 35 to 45 

Automatic expansion gear N.C. 80 30 to 35 

Automatic expansion gear N.C. 100 26 to 30 

Compound automatic expansion gear . N.C. 100 24 to 28 

Compound automatic expansion gear . C. 100 18 to 24 

Compound automatic expansion gear . N.C. 125 21 to 25 

Compound automatic expansion gear . C. 125 16 to 20 

Simple Corliss N.C. 80 25 to 30 

Simple Corliss C. 80 22 to 25 

Compound Corliss C. 100 16 to 20 

Compound Corliss C. 125 15 to 19 

Triple expansion C. 125 14 to 16 

Triple expansion C. 150 13 to 15 

Compound superheated steam C. i8< 10 to 12 

C, condensing; N.C, non-condensing. 



INDEX 



PAGES 

Air Compressors on New York Tunnel Work 185-204 

Air Compressor Plant: 

Belmont Tunnels 148-152 

Bergen Hill Tunnel 53 — 55 

Cross-Town Tunnels P. R.R 105-106 

East River Tunnels, P. R.R 114-121 

Hudson-Manhattan Tunnels 166-167 

North River Tunnels, Manhattan Side, P. R.R 58-62 

North River Tunnels, Weehawken Side, P. R.R 58-62 

P. R.R. Terminal Station 92 

Air Power Plant: 

Belmont Tunnels 148-152 

Bergen Hill Tunnel 53 — 55 

Cross-Town Tunnels, P. R.R 105-106 

East River Tunnels, P. R.R 114-121 

Hudson-Manhattan Tunnels 166-167 

North River Tunnels, Manhattan Side, P. R.R 58-62 

North River Tunnels, Weehawken Side, P. R.R 58-62 

P. R.R. Terminal Station 92 

Air Cylinder Lubrication 249-250 

Air-Lift Data 251-255 

Altitude Compression 246-249 

Beach Pneumatic Railway 5 

Belmont Tunnels 148-153 

' ' " Air-Power Plant 148-152 

Bends 13 

Bergen Hill Tunnel, P. R.R.: 

Compressed Air Requirements 54~55 

Contractor's Plant 53~ 55 

Developments 39 

Drilling Cost 48-49 

Drill Steel Used 47-48 

Explosives 48 

Quantities of Materials Used 56 

Simplon Tunnel Compared 49 

367 



368 INDEX 



Bergen Hill Tunnel, P.R.R. — Continued. 

Typical Cross-section 47 

Ventilation . . . : 51 

Blasting Gelatine 312 

Blasting, Cost of, North River Tunnels 78-80 

Blasting in Open Cuts, Cost of 312-318 

' ' , Tunnel, Explosives for 307-310 

Brickwork, Cost of, in New York Subway 36 

Bridge Caissons 334~338 

Broadway Underground Railway 5 

Brooklyn-Manhattan Division, New York Subway: 

Cost 27 

East River Tunnels 30 

Methods of Excavation 28 

Route 27 

Structural Designs 27 

Cameron Pump and Ingersoll Drill 278-280 

Caissons, Bridge 334 _ 338 

Caisson Disease 207-209 

Caissons, Pneumatic 322-334 

334-338 

Classification of Compressor Types 213-214 

Comparison of Costs — Steam and Compressed Air 33 

Compound Air Compression 237-246 

Compressed Air in Subway Construction 32 

Compressed-Air Locomotives 256-261 

Compressed- Air Plenum 205-209 

Compressed- Air Requirements, Bergen Hill Tunnel, P. R.R 54 - 55 

Concrete, Cost of, in New York Subway 36 

Concrete Cost, North River Tunnels, P. R.R 85-87 

Contractors' Plant, Bergen Hill Tunnel, P. R.R 53 _ 55 

Contractors' Equipment, Cross-Town Tunnels, P. R.R 105-106 

Contractors' Plant, P. R.R. Terminal Station 93 

Cost of Brickwork, New York Subway 36 

Blasting in Open Cut 312-318 

North River Tunnels, P. R.R .'..- 78-80 

Concrete— North River Tunnels, P. R.R 85-87 

in New York Subway 36 

Crushed Stone — North River Tunnels, P. R.R 63 

Drilling— Bergen Hill Tunnels, P. R.R 48-49 

' ' — Electric-Air Drill 292-294 

' ' —North River Tunnels, P. R.R 70-71-79-80-81 

Drill Sharpening 304 

Earthwork in New York Subway 36 

Excavation — North River Tunnels, P. R.R 80 

Cost, Estimated, P. R.R. Developments 39 



INDEX 300 

PACKS 

Cost of Labor — North River Tunnels, P. R.R. . . 69-70, 71-72, 74, 79, 81, 84, 86, 87 

Mucking — North River Tunnels, P. R.R 70, 72, 74, 79, 81, 84, 

Open Cut Excavation in New York Subway 34 

Operating Power Plant — North River Tunnels, P. R.R 61-62 

Timbering — North River Tunnels, P. R.R 72-74 

Shaft Sinking — East River Tunnels, P. R.R 134-135 

.Cross-Town Tunnels, P. R.R.: 

Air-Power Plant 105-106 

Contractors' Equipment 105-106 

Disposal of Material 106 

Methods of Excavation 107-110 

Crushed Stone, Cost of, North River Tunnels, P. R.R 63 

Dampness and Dynamite 311 

Drilling Cost, Bergen Hill Tunnel, P. R.R 48-49 

Drilling and Blasting, Cost of, North River Tunnels, P. R.R 78-80 

Drilling Cost, North River Tunnels, P. R.R 70, 71, 79. 80, 81 

Drill Steel, Bergen Hill Tunnel, P. R.R 47-48 

Dynamite, Dampness and 311 

Earthwork, Cost of, New York Subway 36 

East River Gas Tunnel 10 

East River Tunnels, P. R.R n 1-147 

Air Consumption 143-145 

Air- Power Plant 114-121 

Air Pressures Carried 132 

Clay Blanket 145 

Cost of Shaft Sinking 134-135 

Costs of Various Operations , 147 

Developments 41-42 

Materials and Formation Penetrated 126-127 

Methods of Excavation 135-142 

Methods of Lining 145 

Shaft Sinking i33~i35 

Shield Construction and Operation 123-132 

Specifications of Contract 1 n-i 14 

Working Gangs in Air Pressure 132 

Electric-Air Drill 283-292 

" " Cost of Drilling 292-294 

Electric Driven Compressors 217 

Elevated Railways, Original 4-6 

Engineering Data 340-365 

Excavation, Cost of, North River Tunnels, P. R.R 80 

" Methods of, P. R.R. Terminal Station 96-98, 100-103 

Explosives, Bergen Hill Tunnel, P. R.R 48 

, North River Tunnels, P. R.R 70 

" for Tunnel Blasting 3°7 _ 3io 

< ' Terminal Station, P. R.R 103 



370 INDEX 

PAGES 

Foundation Problems in New York City 322-334 

Geological Formation of Manhattan Island 1-6 

Gray Canon Quarry 33 

Hammer Drills 270 

Harlem River Tunnel, New York Subway 23 

Historical Data on New York Rapid Transit 1-6 

Hudson Manhattan Tunnels 155-167 

Air-Power Plant 166-167 

Caisson Construction 163-165 

Method of Lining 160 

Hudson Terminal Station 168-181 

Caisson Construction . . . 174-176 

Method of Construction 174-176 

Quantities of Materials 176 

Traffic Arrangements 169-173 

Hudson Tunnel, Original 7 

Hydraulic Air Compressor 219-225 

Ingersoll Drill and Cameron Pump 278-280 

Labor Costs — North River Tunnels, P. R.R. . . 69, 70, 71, 72, 74, 79, 81, 84, 86, 87 

Manhattan-Bronx Division, New York Subway 16 

Amount and Character of Excavation 26 

Blasting and Drilling 21 

Division by Sections, Prices 16 

Harlem River Tunnel 23 

Length 26 

Quantities of Materials 26 

Structural Design 18 

Meadows Division, P. R.R., Developments 39 

Methods of Excavation, Cross-Town Tunnels, P. R.R 107-110 

" East River Tunnels, P. R.R 135-142 

Mucking Cost, North River Tunnels, P. R.R 70, 72, 74, 79, 81, 84 

New York Subway 16-36 

Cost of Brickwork 36 

Cost of Concrete 36 

Cost of Earthwork 36 

Cost of Excavation in Open Cut 34 

Wages Paid in Construction 35 

North River Bridge Co 37 

North River Tunnels, P.R.R.: 

Analysis of Drilling Operations 78-80 

Developments 39 

Bulkheads 70-71 

Concrete Cost 85-87 



TNDEX 371 

PAGES 

North River Tunnels, P. R.R. : — Continued. 

Cost of Crushed Stone 63 

Cost of Drilling 70, 71, 79, 80, 81 

Cost of Drilling and Blasting 78-80 

Cost of Driving Shields 70, 72, 74, 84 

Cost of Erecting Lining 70, 72, 74, 84 

Cost of Excavation 80 

Cost of Mucking 70, 72, 74, 79, 81, 84 

Cost of Power Plant Operation 61-62 

Cost of Tunneling 72, 74 

Crushed Stone Plant 63 

Explosives 77 

Manhattan Power Plant 62-68 

Manhattan Shaft 57 

Quantities of Materials Used 90 

Shield 64-69 

Typical Cross-sections ' 62, 65 

Weehawken Power Plant 58-62 

Weehawken Shaft 57 

Open Cut, Cost of Blasting in 312-318 

' ' , Excavation, Cost of, in New York Subway 34 

P. R.R. Developments in Xew York City 37 - 45 

' ' Terminal Excavation 91-103 

Pit Sinking in Frozen Quicksand 338-339 

Plug Drills 270 

Pneumatic Caissons 322-334, 334-338 

Preface vii-ix 

Prevention of Caisson Disease 207-209 

Pumps for Sinking and Tunneling 319-322 

Quicksand, Pit Sinking in 338-339 

Retaining Walls, P. R.R. Terminal Station 94-96 

Rock Drill Bits 295-304 

Rock Drilling Methods, P. R.R. Terminal Station 97-103 

Rock Drill Mountings 268-270 

Rock Drills and Mountings 262-270 

Sharpening 305-306 

Rules for Working in Compressed Air 12 

Shield Construction and Operation, East River Tunnels, P. R.R 123-132 

Simplon Tunnel, Comparison of, with Bergen Hill Tunnels 49 

Special Types of Air Compressors 217-225 

Steam, Useful Information on 350-351 

Straight Line and Duplex Compressors 226-236 



372 INDEX 

PAGES 

Tables: 

Air Required by Rock Drills 340 

Areas of Circles 354 

Capacity of Pumps 357 

Coal Consumption of Engines 364 

Compressed Air for Pumping Plants 349 

Compressor Capacity for Rock Drills 341 

Contents of Cylinders 358 

Density of Gases and Vapors 348 

Feed Water Consumption of Engines . 365 

Flow of Air through an Orifice 348 

Friction Losses in Fire Hose 363 

Friction Losses in Water Pipes 361-362 

Heat of Combustion in Fuels 365 

Heights for Pumping Water 359 

Horse-power Required to Compress Air 346 

Loss of Air Pressure in Valves, Tees, and Elbows 346 

Loss of Air Pressure in Transmission 342-345 

Loss of Work Due to Heat in Air Consumption 347 

Metric Measures 364 

Pressure of Water 353 

Ratio of Cylinder Areas 355 _ 356 

Standard Pipe Dimensions 360 

Water Jets 363 

Terminal Station, P. R.R. 

Air-Power Plant 92 

Contractor's Equipment 93 

Developments 39~4 I 

Disposal of Materials 98-102 

Explosives 103 

Methods of Excavation 96-98, 100-103 

Quantity of Materials 98-103 

Retaining Walls 94-96 

Rock Drilling Methods 97-103 

Topography of Manhattan Island 1-6 

Train Movement, P. R.R. Terminal 45 

Tribute v-vi 

Tunnel Carriage for Drilling 281-283 

Timbering Cost — North River Tunnels, P. R.R 72-74 

Tunnel Shield— North River Tunnels, P. R.R. 64-69 

Use of Compressed Air in Tunneling 210-216 

Ventilation in Bergen Hill Tunnels . . . 5 1 

Water Impulse Compressors 217 

' ' , Useful Information on 35 I- 35 2 

Wages in New York Subway Construction 35 



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* Tillman's Descriptive General Chemistry 8vo, 

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Bovey's Treatise on Hydraulics 8vo, $5 00 

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* Lead and Zinc Pigments Large 12mo, 3 00 

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* Hubbard's Dust Preventives and Road Binders 8vo, $3 00 

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Maire's Modern Pigments and their Vehicles 12mo, 

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* " " " Abridged Ed 8vo, 150 

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14 



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8vo, $4 00 

Weisbach's Heat. Steam, and Steam-engines. (Du Bois.) 8vo, 5 00 

Whitham's Steam-engine Design 8vo. 5 00 

Woori's Thermodynamics, Heat Motors, and Refrigerating Machines. . ,8vo, 4 00 

MECHANICS PURE AND APPLIED. 

Church's Mechanics of Engineering 8vo, 

Mechanics of Fluids (Being Part IV of Mechanics of Engineering). .8vo, 

* Mechanics of Internal Work 8vo, 

Mechanics of Solids (Being Parts I, II, III of Mechanics of Engineering). 

8vo, 

Notes and Examples in Mechanics : . 8vo, 

Dana's Text-book of Elementary Mechanics for Colleges and Schools .12mo, 
Du Bois's Elementary Principles of Mechanics: 

Vol. I. Kinematics 8vo, 

Vol. II. Statics 8vo, 

Mechanics of Engineering. Vol. I Small 4to, 

Vol. II Small 4to, 

* Greene's Structural Mechanics 8vo, 

* Hartmann's Elementary Mechanics for Engineering Students 12mo, 

James's Kinematics of a Point and the Rational Mechanics of a Particle. 

Large 12mo. 

* Johnson's (W. W.) Theoretical Mechanics 12mo, 

* King's Elements of the Mechanics of Materials and of Power of Trans- 

mission 8vo, 

Lanza's Applied Mechanics 8vo, 

* Martin's Text Book on Mechanics, Vol. I, Statics 12mo, 

* Vol. II. Kinematics and Kinetics 12mo, 

* Vol. III. Mechanics of Materials 12mo, 

Maurer's Technical Mechanics 8vo. 

* Merriman's Elements of Mechanics 12mo, 

Mechanics of Materials 8vo, 

* Michie's Elements of Analytical Mechanics 8vo, 

Robinson's Principles of Mechanism 8vo, 

Sanborn's Mechanics Problems Large 12mo, 

Schwamb and Merrill's Elements of Mechanism 8vo, 

Wood's Elements of Analytical Mechanics 8vo, 

Principles of Elementary Mechanics 12mo, 

MEDICAL. 

* Abderhalden's Physiological Chemistry in Thirty Lectures. (Hall and 

Defren.) 8vo, 5 00 

von Behring's Suppression of Tuberculosis. (Bolduan.) 12mo, 1 00 

* Bolduan's Immune Sera 12tno, 1 50 

Bordet's Studies in Immunity. (Gay.) 8vo, 6 00 

* Chapin's The Sources and Modes of Infection Large 12mo, 3 00 

Davenport's Statistical Methods with Special Reference to Biological Varia- 
tions 16mo, mor. 1 50 

Ehrlich's Collected Studies on Immunity. (Bolduan.) 8vo, 6 00 

* Fischer's Nephritis Large 12mo, 2 50 

* Oedema ; 8vo, 2 00 

* Physiology of Alimentation Large 12mo, 2 00 

* de Fursac's Manual of Psychiatry. (Rosanoff and Collins.) . . . Large 12mo, 2 50 

* Hammarsten's Text-book on Physiological Chemistry. (Mandel.).. . .8vo, 4 00 
Jackson's Directions for Laboratory Work in Physiological Chemistry. .8vo, 1 25 

Lassar-Cohn's Praxis of Urinary Analysis. (Lorenz.) 12mo, 1 00 

Mandel's Hand-book for the Bio-Chemical Laboratory 12mo. 1 50 

* Nelson's Analysis of Drugs and Medicines 12mo. 3 00 

* Pauli's Physical Chemistry in the Service of Medicine. (Fischer.) ..12mo, 1 25 

* Pozzi-Escot's Toxins and Venoms and their Antibodies. (Cohn.). . 12mo, 1 00 

Rostoski's Serum Diagnosis. (Bolduan.) 12mo, 1 00 

Ruddiman's Incompatibilities in Prescriptions 8vo, 2 00 

Whys in Pharmacy 12mo, 1 00 

Salkowski's Physiological and Pathological Chemistry. (Orndorff.) .. ..8vo, 2 50 

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* Satterlee's Outlines of Human Embryology 12mo, 

Smith's Lecture Notes on Chemistry for Dental Students 8vo, 

* Whipple's Tyhpoid Fever Large 12mo, 

* Woodhull's Military Hygiene for Officers of the Line Large 12mo, 

* Personal Hygiene 12mo, 

Worcester and Atkinson's Small Hospitals Establishment and Maintenance, 
and Suggestions for Hospital Architecture, with Plans for a Small 
Hospital 12mo, 



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METALLURGY. 

Betts's Lead Refining by Electrolysis 8vo, 

Bolland's Encyclopedia of Founding and Dictionary of Foundry Terms used 

in the Practice of Moulding 12mo 

Iron Founder 12mo 

Supplement 12mo 

* Borchers's Metallurgy. (Hall and Hayward.) 8vo 

* Burgess and Le Chatelier's Measurement of High Temperatures. Third 

Edition 8vo 

Douglas's Untechnical Addresses on Technical Subjects 12mo 

Goesel's Minerals and Metals: A Reference Book 16mo, mor 

* Iles's Lead-smelting 12mo 

Johnson's Rapid Methods for the Chemical Analysis of Special Steels 

Steel-making Alloys and Graphite Large 12mo 

Keep's Cast Iron 8vo 

Metcalf 's Steel. A Manual for Steel-users 12mo 

Minet's Production of Aluminum and its Industrial Use. (Waldo.). . 12mo 

* Palmer's Foundry Practice Large 12mo 

* Price and Meade's Technical Analysis of Brass 12mo 

* Ruer's Elements of Metallography. (Mathewson.) 8vo 

Smith's Materials of Machines 12mo 

Tate and Stone's Foundry Practice 12mo 

Thurston's Materials of Engineering. In Three Parts 8vo 

Part I. Non-metallic Materials of Engineering, see Civil Engineering 
page 9. 

Part II. Iron and Steel 8vo 

Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their 

Constituents 8vo 

Ulke's Modern Electrolytic Copper Refining 8vo 

West's American Foundry Practice 12mo 

Moulders' Text Book 12mo. 



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MINERALOGY. 

* Browning's Introduction to the Rarer Elements 8vo, 

Brush's Manual of Determinative Mineralogy. (Penfield.) 8vo, 

Butler's Pocket Hand-book of Minerals 16mo, mor. 

Chester's Catalogue of Minerals 8vo, paper, 

Cloth, 

* Crane's'Gold and Silver „ 8vo, 

Dana's First Appendix to Dana's New "System of Mineralogy". .Large 8vo, 
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Large 8vo, 

Manual of Mineralogy and Petrography 12mo, 

Minerals and How to Study Them 12mo, 

System of Mineralogy .Large 8vo, half leather, 

Text-book of Mineralogy 8vo, 

Douglas's Untechnical Addresses on Technical Subjects 12mo, 

Eakle's Mineral Tables 8vo, 

* Eckel's Building Stones and Clays . 8vo, 

Goesel's Minerals and Metals: A Reference Book 16mo, mor. 

* Groth's The Optical Properties of Crystals. (Jackson.) 8vo, 

Groth's Introduction to Chemical Crystallography (Marshall) 12mo, 

* Hayes's Handbook for Field Geologists 16mo, mor. 

Iddings's Igneous Rocks 8vo, 

Rock Minerals 8vo, 

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Johannsen's Determination of Rock-forming Minerals in Thin Sections. 8vo, 

With Thumb Index $5 00 

* Martin's Laboratory Guide to Qualitative Analysis with the Blow- 

pipe « 12mo, 60 

Merrill's Non-metallic Minerals: Their Occurrence and Uses 8vo, 4 00 

Stones for Building and Decoration 8vo, 5 00 

* Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 

8vo, paper, 50 
Tables of Minerals, Including the Use of Minerals and Statistics of 

Domestic Production 8vo, 1 00 

* Pirsson's Rocks and Rock Minerals 12mo, 2 50 

* Richards's Synopsis of Mineral Characters 12mo, mor. 1 25 

* Ries's^Clays: Their Occurrence, Properties and Uses 8vo, 5 00 

* Ries and Leighton's History of the Clay-working maustry of the United 

States 8vo, 2 50 

* Rowe's Practical Mineralogy Simplified 12mo, 1 25 

* Tillman's Text-book of Important Minerals and Rocks 8vo, 2 00 

Washington's Manual of the Chemical Analysis of Rocks 8vo, 2 00 

MINING. 

* Beard's Mine Gases and Explosions Large 12mo, 3 00 

* Crane's Gold and Silver 8vo, 5 00 

* Index of Mining Engineering Literature 8vo, 4 00 

* 8vo, mor. 5 00 

* Ore Mining Methods 8vo, 3 00 

* Dana and Saunders's Rock Drilling 8vo, 4 00 

Douglas's Untechnical Addresses on Technical Subjects 12mo, 1 00 

Eissler's Modern High Explosives 8vo, 4 00 

Goesel's Minerals and Metals: A Reference Book 16mo, mor. 3 00 

Ihlseng's Manual of Mining 8vo, 5 00 

* Iles's Lead Smelting 12mo, 2 50 

* Peele's Compressed Air Plant 8vo, 3 50 

Riemer's Shaft Sinking Under Difficult Conditions. (Corning and Peele.)8vo, 3 00 

* Weaver's Military Explosives , 8vo, 3 00 

Wilson's Hydraulic and Placer Mining. 2d edition, rewritten 12mo, 2 50 

Treatise on Practical and Theoretical Mine Ventilation 12mo, 1 25 

SANITARY SCIENCE. 

Association of State and National Food and Dairy Departments, Hartford 

Meeting, 1906 8vo, 3 00 

Jamestown Meeting, 1907 8vo, 3 00 

* Bashore's Outlines of Practical Sanitation 12mo, 1 25 

Sanitation of a Country House 12mo, 1 00 

Sanitation of Recreation Camps and Parks 12mo, 1 00 

* Chapin's The Sources and Modes of Infection Large 12mo, 3 00 

Folwell's Sewerage. (Designing, Construction, and Maintenance.) 8vo, 3 00 

Water-supply Engineering 8vo, 4 00 

Fowler's Sewage Works Analyses 12mo, 2 00 

Fuertes's Water-filtration Works 12mo, 2 50 

Water and Public Health 12mo, 1 50 

Gerhard's Guide to Sanitary Inspections 12mo, 1 50 

* Modern Baths and Bath Houses 8vo, 3 00 

Sanitation of Public Buildings 12mo, 1 50 

* The Water Supply, Sewerage, and Plumbing of Modern City Buildings. 

8vo, 4 00 

Hazen's Clean Water and How to Get It Large 12mo, 1 50 

Filtration of Public Water-supplies 8vo, 3 00 

* Kinnicutt, Winslow and Pratt's Sewage Disposal 8vo, 3 00 

Leach's Inspection and Analysis of Food with Special Reference to State 

Control 8vo, 7 50 

Mason's Examination of Water. (Chemical and Bacteriological) 12mo, 1 25 

Water-supply. (Considered principally from a Sanitary Standpoint). 

8vo, 4 00 

* Mast's Light and the Behavior of Organisms Large 12mo, 2 50 

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::: Merriman's Elements of Sanitary Engineering 8vo, 

Ogden's Sewer Construction 8vo, 

Sewer Design 12mo, 

Parsons's Disposal of Municipal Refuse 8vo, 

Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- 
ence to Sanitary Water Analysis 12mo, 

* Price's Handbook on Sanitation 12mo, 

Richards's Conservation by Sanitation 8vo, 

Cost of Cleanness 12mo, 

Cost of Food. A Study in Dietaries 12mo, 

Cost of Living as Modified by Sanitary Science 12mo, 

Cost of Shelter 12mo, 

Richards and Woodman's Air, Water, and Food from a Sanitary Stand- 
point 8vo, 

* Richey's Plumbers', Steam-fitters', and Tinners' Edition (Building 

Mechanics' Ready Reference Series) 16mo, mor. 

Rideal's Disinfection and the Preservation of Food 8vo, 

Soper's Air and Ventilation of Subways 12mo, 

Turneaure and Russell's Public Water-supplies 8vo, 

Venable's Garbage Crematories in America 8vo 

Method and Devices for Bacterial Treatment of Sewage 8vo, 

Ward and Whipple's Freshwater Biology. (In Press.) 

Whipple's Microscopy of Drinking-water 8vo, 

* Typhoid Fever Large 12mo, 

Value of Pure Water Large 12mo, 

Winslow's Systematic Relationship of the Coccaceae Large 12mo, 

MISCELLANEOUS. 

* Burt's Railway Station Service 12mo, 

* Chapin's How to Enamel 12mo. 

Emmons's Geological Guide-book of the Rocky Mountain Excursion of the 

International Congress of Geologists Large 8vo, 

Ferrel's Popular Treatise on the Winds 8vo, 

Fitzgerald's Boston Machinist 18mo, 

* Fritz, Autobiography of John 8vo, 

Gannett's Statistical Abstract of the World 24mo, 

Haines's American Railway Management 12mo, 

Hanausek's The Microscopy of Technical Products. (Winton) 8vo, 

Jacobs's Betterment Briefs. A Collection of Published Papers on Or- 
ganized Industrial Efficiency 8vo, 

Metcalfe's Cost of Manufactures, and the Administration of Workshops. .8vo, 

* Parkhurst's Applied Methods of Scientific Management 8vo, 

Putnam's Nautical Charts 8vo, 

Ricketts's History of Rensselaer Polytechnic Institute 1824-1894. 

Large 12mo, 

* Rotch and Palmer's Charts of the Atmosphere for Aeronauts and Aviators. 

Oblong 4to, 

Rotherham's Emphasised New Testament Large 8vo, 

Rust's Ex-Meridian Altitude, Azimuth and Star-finding Tables 8vo 

Standage's Decoration of Wood, Glass, Metal, etc = . t 12mo 

Thome's Structural and Physiological Botany. (Bennett) 16mo, 

Westermaier's Compendium of General Botany. (Schneider) 8vo, 

Winslow's Elements of Applied Microscopy 12mo, 

HEBREW AND CHALDEE TEXT-BOOKS. 

Gesenius's Hebrew and Chaldee Lexicon to the Old Testament Scriptures. 

(Tregeiles.) Small 4to. half mor, 5 00 

Green's Elementary Hebrew Grammar 12mo 1 25 



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